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100
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1 from .symboltable import SymbolTable
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70
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2 from .nodes import *
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102
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3 from .builtin import *
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101
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4 from .lexer import tokenize
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100
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5
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6 class KsParser:
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106
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7 """ This module parses source code into an abstract syntax tree (AST) """
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101
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8 def __init__(self, source):
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100
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9 """ provide the parser with the tokens iterator from the lexer. """
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101
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10 self.tokens = tokenize(source) # Lexical stage
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100
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11 self.NextToken()
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12 self.errorlist = []
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13
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14 def Error(self, msg):
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15 raise CompilerException(msg, self.token.row, self.token.col)
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16
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17 # Lexer helpers:
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18 def Consume(self, typ=''):
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19 if self.token.typ == typ or typ == '':
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20 v = self.token.val
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21 self.NextToken()
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22 return v
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23 else:
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24 self.Error('Excected: "{0}", got "{1}"'.format(typ, self.token.val))
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25
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26 def hasConsumed(self, typ):
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27 if self.token.typ == typ:
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28 self.Consume(typ)
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29 return True
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30 return False
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31
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32 def NextToken(self):
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33 self.token = self.tokens.__next__()
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34 # TODO: store filename in location?
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35 self.location = (self.token.row, self.token.col)
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36
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37 # Helpers to find location of the error in the code:
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38 def setLocation(self, obj, location):
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39 obj.location = location
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40 return obj
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41 def getLocation(self):
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42 return self.location
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43
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44 """
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45 Recursive descent parser functions:
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46 A set of mutual recursive functions.
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47 Starting symbol is the Module.
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48 """
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49 def parseModule(self):
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101
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50 """ Top level parsing routine """
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100
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51 self.imports = []
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52 loc = self.getLocation()
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53 self.Consume('module')
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54 modname = self.Consume('ID')
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55 self.Consume(';')
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56 mod = Module(modname)
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57
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58 # Construct a symbol table for this program
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59 mod.symtable = SymbolTable()
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60 # Add built in types and functions:
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61 for x in [real, integer, boolean, char, chr_func]:
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62 mod.symtable.addSymbol(x)
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63
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64 self.cst = mod.symtable
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65 self.parseImportList()
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66
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67 self.parseDeclarationSequence()
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68 # Procedures only allowed in this scope
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69 self.parseProcedureDeclarations()
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70
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71 if self.hasConsumed('begin'):
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72 mod.initcode = self.parseStatementSequence()
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73 else:
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74 mod.initcode = EmptyStatement()
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75
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76 self.Consume('end')
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77 endname = self.Consume('ID')
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78 if endname != modname:
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79 self.Error('end denoter must be module name')
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80 self.Consume('.')
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81
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82 mod.imports = self.imports
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83 return self.setLocation(mod, loc)
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84
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85 # Import part
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86 def parseImportList(self):
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87 if self.hasConsumed('import'):
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88 self.parseImport()
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89 while self.hasConsumed(','):
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90 self.parseImport()
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91 self.Consume(';')
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92
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93 def parseImport(self):
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94 loc = self.getLocation()
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95 modname = self.Consume('ID')
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110
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96 # TODO: fix
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101
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97 #mod = loadModule(modname)
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98 self.setLocation(mod, loc)
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99 self.cst.addSymbol(mod)
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100
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101 # Helper to parse an identifier defenitions
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102 def parseIdentDef(self):
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103 loc = self.getLocation()
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104 name = self.Consume('ID')
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105 ispublic = self.hasConsumed('*')
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106 # Make a node of this thing:
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107 i = Id(name)
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108 i.ispublic = ispublic
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109 return self.setLocation(i, loc)
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110
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111 def parseIdentList(self):
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112 ids = [ self.parseIdentDef() ]
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113 while self.hasConsumed(','):
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114 ids.append( self.parseIdentDef() )
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115 return ids
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116
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117 def parseQualIdent(self):
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118 """ Parse a qualified identifier """
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119 name = self.Consume('ID')
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120 if self.cst.has(Module, name):
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121 modname = name
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122 mod = self.cst.get(Module, modname)
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123 self.Consume('.')
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124 name = self.Consume('ID')
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125 # Try to find existing imported symbol:
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126 for imp in self.imports:
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127 if imp.modname == modname and imp.name == name:
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128 return imp
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129 # Try to find the symbol in the modules exports:
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130 for sym in mod.exports:
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131 if sym.name == name:
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132 impsym = ImportedSymbol(modname, name)
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133 impsym.typ = sym.typ
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134 impsym.signature = mod.signature
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135 self.imports.append(impsym)
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136 return impsym
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137 self.Error("Cannot find symbol {0}".format(name))
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138 else:
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139 return self.cst.getSymbol(name)
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70
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140
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100
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141 # Helper to parse a designator
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142 def parseDesignator(self):
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143 """ A designator designates an object.
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144 The base location in memory is denoted by the qualified identifier
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145 The actual address depends on the selector.
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146 """
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147 loc = self.getLocation()
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148 obj = self.parseQualIdent()
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149 typ = obj.typ
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150 selectors = []
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151 while self.token.typ in ['.', '[', '^']:
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152 if self.hasConsumed('.'):
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153 field = self.Consume('ID')
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154 if typ is PointerType:
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155 selectors.append(Deref())
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156 typ = typ.pointedType
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157 if not type(typ) is RecordType:
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158 self.Error("field reference, type not record but {0}".format(typ))
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159 typ = typ.fields[field]
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160 selectors.append(Field(field))
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161 elif self.hasConsumed('['):
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162 indexes = self.parseExpressionList()
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163 self.Consume(']')
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164 for idx in indexes:
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165 if not type(typ) is ArrayType:
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166 self.Error('Cannot index non array type')
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167 if not isType(idx.typ, integer):
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168 self.Error('Only integer expressions can be used as an index')
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169 selectors.append(Index(idx, typ))
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170 typ = typ.elementType
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171 elif self.hasConsumed('^'):
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172 selectors.append(Deref())
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173 typ = typ.pointedType
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174 return self.setLocation(Designator(obj, selectors, typ), loc)
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175
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176 # Declaration sequence
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177 def parseDeclarationSequence(self):
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178 """ 1. constants, 2. types, 3. variables """
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179 self.parseConstantDeclarations()
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180 self.parseTypeDeclarations()
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181 self.parseVariableDeclarations()
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182
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183 # Constants
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184 def evalExpression(self, expr):
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185 if type(expr) is Binop:
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186 a = self.evalExpression(expr.a)
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187 b = self.evalExpression(expr.b)
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188 if expr.op == '+':
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189 return a + b
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190 elif expr.op == '-':
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191 return a - b
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192 elif expr.op == '*':
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193 return a * b
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194 elif expr.op == '/':
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195 return float(a) / float(b)
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196 elif expr.op == 'mod':
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197 return int(a % b)
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198 elif expr.op == 'div':
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199 return int(a / b)
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200 elif expr.op == 'or':
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201 return a or b
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202 elif expr.op == 'and':
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203 return a and b
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204 else:
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205 self.Error('Cannot evaluate expression with {0}'.format(expr.op))
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206 elif type(expr) is Constant:
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207 return expr.value
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208 elif type(expr) is Designator:
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209 if type(expr.obj) is Constant:
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210 return self.evalExpression(expr.obj)
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211 else:
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212 self.Error('Cannot evaluate designated object {0}'.format(expr.obj))
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213 elif type(expr) is Unop:
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214 a = self.evalExpression(expr.a)
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215 if expr.op == 'not':
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216 return not a
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217 elif expr.op == '-':
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218 return -a
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219 else:
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220 self.Error('Unimplemented unary operation {0}'.format(expr.op))
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221 else:
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222 self.Error('Cannot evaluate expression {0}'.format(expr))
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223
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110
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224 def parseConstant(self):
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225 e = self.parseExpression()
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226 val = self.evalExpression(e)
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227 return Constant(val, e.typ)
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228
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229 def parseConstantDeclarations(self):
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230 """ Parse const part of a module """
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231 if self.hasConsumed('const'):
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232 while self.token.typ == 'ID':
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233 i = self.parseIdentDef()
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234 self.Consume('=')
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110
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235 c = self.parseConstant()
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236 self.Consume(';')
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110
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237 c.name = i.name
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238 c.public = i.ispublic
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239 self.setLocation(c, i.location)
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240 self.cst.addSymbol(c)
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241
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242 # Type system
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243 def parseTypeDeclarations(self):
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244 if self.hasConsumed('type'):
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245 while self.token.typ == 'ID':
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246 typename, export = self.parseIdentDef()
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247 self.Consume('=')
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248 typ = self.parseStructuredType()
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249 self.Consume(';')
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250 t = DefinedType(typename, typ)
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251 self.cst.addSymbol(t)
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252
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253 def parseType(self):
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254 if self.token.typ == 'ID':
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255 typename = self.Consume('ID')
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256 if self.cst.has(Type, typename):
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257 typ = self.cst.get(Type, typename)
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258 while type(typ) is DefinedType:
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259 typ = typ.typ
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260 return typ
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261 else:
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262 self.Error('Cannot find type {0}'.format(typename))
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263 else:
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264 return self.parseStructuredType()
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265
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266 def parseStructuredType(self):
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267 if self.hasConsumed('array'):
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268 dimensions = []
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110
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269 dimensions.append( self.parseConstant() )
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270 while self.hasConsumed(','):
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110
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271 dimensions.append( self.parseConstant() )
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100
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272 self.Consume('of')
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273 arr = self.parseType()
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110
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274 for dimension in reversed(dimensions):
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275 if not isType(dimension.typ, integer):
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100
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276 self.Error('array dimension must be an integer type (not {0})'.format(consttyp))
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110
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277 if dimension.value < 2:
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278 self.Error('array dimension must be bigger than 1 (not {0})'.format(dimension.value))
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279 arr = ArrayType(dimension.value, arr)
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100
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280 return arr
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281 elif self.hasConsumed('record'):
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282 fields = {}
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283 while self.token.typ == 'ID':
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284 # parse a fieldlist:
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285 identifiers = self.parseIdentList()
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286 self.Consume(':')
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287 typ = self.parseType()
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288 self.Consume(';')
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289 for i in identifiers:
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290 if i.name in fields.keys():
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291 self.Error('record field "{0}" multiple defined.'.format(i.name))
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292 fields[i.name] = typ
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293 # TODO store this in another way, symbol table?
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294 self.Consume('end')
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295 return RecordType(fields)
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296 elif self.hasConsumed('pointer'):
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297 self.Consume('to')
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298 typ = self.parseType()
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299 return PointerType(typ)
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300 elif self.hasConsumed('procedure'):
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301 parameters, returntype = self.parseFormalParameters()
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302 return ProcedureType(parameters, returntype)
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303 else:
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304 self.Error('Unknown structured type "{0}"'.format(self.token.val))
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305
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100
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306 # Variable declarations:
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307 def parseVariableDeclarations(self):
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308 if self.hasConsumed('var'):
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309 if self.token.typ == 'ID':
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310 while self.token.typ == 'ID':
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311 ids = self.parseIdentList()
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312 self.Consume(':')
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313 typename = self.parseType()
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314 self.Consume(';')
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315 for i in ids:
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316 v = Variable(i.name, typename, public=i.ispublic)
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317 self.setLocation(v, i.location)
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318 self.cst.addSymbol(v)
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319 else:
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320 self.Error('Expected ID, got'+str(self.token))
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321
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322 # Procedures
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323 def parseFPsection(self):
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324 if self.hasConsumed('const'):
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325 kind = 'const'
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326 elif self.hasConsumed('var'):
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327 kind = 'var'
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328 else:
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329 kind = 'value'
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330 names = [ self.Consume('ID') ]
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331 while self.hasConsumed(','):
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332 names.append( self.Consume('ID') )
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333 self.Consume(':')
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334 typ = self.parseType()
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335 parameters = [Parameter(kind, name, typ)
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336 for name in names]
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337 return parameters
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338
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339 def parseFormalParameters(self):
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340 parameters = []
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341 self.Consume('(')
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342 if not self.hasConsumed(')'):
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343 parameters += self.parseFPsection()
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344 while self.hasConsumed(';'):
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345 parameters += self.parseFPsection()
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346 self.Consume(')')
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347 if self.hasConsumed(':'):
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348 returntype = self.parseQualIdent()
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349 else:
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350 returntype = void
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351 return ProcedureType(parameters, returntype)
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352
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353 def parseProcedureDeclarations(self):
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354 procedures = []
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355 while self.token.typ == 'procedure':
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356 p = self.parseProcedureDeclaration()
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357 procedures.append(p)
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358 self.Consume(';')
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359 return procedures
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360
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361 def parseProcedureDeclaration(self):
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362 loc = self.getLocation()
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363 self.Consume('procedure')
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364 i = self.parseIdentDef()
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365 procname = i.name
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366 proctyp = self.parseFormalParameters()
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367 procsymtable = SymbolTable(parent = self.cst)
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368 self.cst = procsymtable # Switch symbol table:
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369 # Add parameters as variables to symbol table:
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370 for parameter in proctyp.parameters:
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371 vname = parameter.name
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372 vtyp = parameter.typ
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373 if parameter.kind == 'var':
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374 vtyp = PointerType(vtyp)
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375 variable = Variable(vname, vtyp, False)
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376 if parameter.kind == 'const':
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377 variable.isReadOnly = True
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378 variable.isParameter = True
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379 self.cst.addSymbol(variable)
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380 self.Consume(';')
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381 self.parseDeclarationSequence()
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382 # Mark all variables as local:
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383 for variable in self.cst.getAllLocal(Variable):
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384 variable.isLocal = True
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385
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386 if self.hasConsumed('begin'):
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387 block = self.parseStatementSequence()
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388 if self.hasConsumed('return'):
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389 returnexpression = self.parseExpression()
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390 else:
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391 returnexpression = None
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392
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393 if proctyp.returntype.isType(void):
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394 if not returnexpression is None:
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395 self.Error('Void procedure cannot return a value')
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396 else:
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397 if returnexpression is None:
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398 self.Error('Procedure must return a value')
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399 if not isType(returnexpression.typ, proctyp.returntype):
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400 self.Error('Returned type {0} does not match function return type {1}'.format(returnexpression.typ, proctyp.returntype))
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401
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402 self.Consume('end')
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403 endname = self.Consume('ID')
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404 if endname != procname:
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405 self.Error('endname should match {0}'.format(name))
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406 self.cst = procsymtable.parent # Switch back to parent symbol table
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407 proc = Procedure(procname, proctyp, block, procsymtable, returnexpression)
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408 self.setLocation(proc, loc)
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409 self.cst.addSymbol(proc)
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410 proc.public = i.ispublic
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411 return proc
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412
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413 # Statements:
|
|
|
414 def parseAssignment(self, lval):
|
|
|
415 loc = self.getLocation()
|
|
|
416 self.Consume(':=')
|
|
|
417 rval = self.parseExpression()
|
|
|
418 if isType(lval.typ, real) and isType(rval.typ, integer):
|
|
|
419 rval = Unop(rval, 'INTTOREAL', real)
|
|
|
420 if type(rval.typ) is NilType:
|
|
|
421 if not type(lval.typ) is ProcedureType and not type(lval.typ) is PointerType:
|
|
|
422 self.Error('Can assign nil only to pointers or procedure types, not {0}'.format(lval))
|
|
|
423 elif not isType(lval.typ, rval.typ):
|
|
|
424 self.Error('Type mismatch {0} != {1}'.format(lval.typ, rval.typ))
|
|
|
425 return self.setLocation(Assignment(lval, rval), loc)
|
|
|
426
|
|
|
427 def parseExpressionList(self):
|
|
|
428 expressions = [ self.parseExpression() ]
|
|
|
429 while self.hasConsumed(','):
|
|
|
430 expressions.append( self.parseExpression() )
|
|
|
431 return expressions
|
|
|
432
|
|
|
433 def parseProcedureCall(self, procedure):
|
|
|
434 self.Consume('(')
|
|
|
435 if self.token.typ != ')':
|
|
|
436 args = self.parseExpressionList()
|
|
|
437 else:
|
|
|
438 args = []
|
|
|
439 self.Consume(')')
|
|
110
|
440 # Type checking:
|
|
100
|
441 parameters = procedure.typ.parameters
|
|
|
442 if len(args) != len(parameters):
|
|
|
443 self.Error("Procedure requires {0} arguments, {1} given".format(len(parameters), len(args)))
|
|
|
444 for arg, param in zip(args, parameters):
|
|
|
445 if not arg.typ.isType(param.typ):
|
|
|
446 print(arg.typ, param.typ)
|
|
|
447 self.Error('Mismatch in parameter')
|
|
|
448 return ProcedureCall(procedure, args)
|
|
70
|
449
|
|
100
|
450 def parseIfStatement(self):
|
|
|
451 loc = self.getLocation()
|
|
|
452 self.Consume('if')
|
|
|
453 ifs = []
|
|
|
454 condition = self.parseExpression()
|
|
|
455 if not isType(condition.typ, boolean):
|
|
|
456 self.Error('condition of if statement must be boolean')
|
|
|
457 self.Consume('then')
|
|
|
458 truestatement = self.parseStatementSequence()
|
|
|
459 ifs.append( (condition, truestatement) )
|
|
|
460 while self.hasConsumed('elsif'):
|
|
|
461 condition = self.parseExpression()
|
|
|
462 if not isType(condition.typ, boolean):
|
|
|
463 self.Error('condition of if statement must be boolean')
|
|
|
464 self.Consume('then')
|
|
|
465 truestatement = self.parseStatementSequence()
|
|
|
466 ifs.append( (condition, truestatement) )
|
|
|
467 if self.hasConsumed('else'):
|
|
|
468 statement = self.parseStatementSequence()
|
|
|
469 else:
|
|
|
470 statement = None
|
|
|
471 self.Consume('end')
|
|
|
472 for condition, truestatement in reversed(ifs):
|
|
|
473 statement = IfStatement(condition, truestatement, statement)
|
|
|
474 return self.setLocation(statement, loc)
|
|
|
475
|
|
|
476 def parseCase(self):
|
|
|
477 # TODO
|
|
|
478 pass
|
|
|
479
|
|
|
480 def parseCaseStatement(self):
|
|
|
481 self.Consume('case')
|
|
|
482 expr = self.parseExpression()
|
|
|
483 self.Consume('of')
|
|
|
484 self.parseCase()
|
|
|
485 while self.hasConsumed('|'):
|
|
|
486 self.parseCase()
|
|
|
487 self.Consume('end')
|
|
|
488
|
|
|
489 def parseWhileStatement(self):
|
|
|
490 loc = self.getLocation()
|
|
|
491 self.Consume('while')
|
|
|
492 condition = self.parseExpression()
|
|
|
493 self.Consume('do')
|
|
|
494 statements = self.parseStatementSequence()
|
|
|
495 if self.hasConsumed('elsif'):
|
|
|
496 self.Error('elsif in while not yet implemented')
|
|
|
497 self.Consume('end')
|
|
|
498 return self.setLocation(WhileStatement(condition, statements), loc)
|
|
|
499
|
|
|
500 def parseRepeatStatement(self):
|
|
|
501 self.Consume('repeat')
|
|
|
502 stmt = self.parseStatementSequence()
|
|
|
503 self.Consume('until')
|
|
|
504 cond = self.parseBoolExpression()
|
|
110
|
505 # TODO
|
|
100
|
506
|
|
|
507 def parseForStatement(self):
|
|
|
508 loc = self.getLocation()
|
|
|
509 self.Consume('for')
|
|
|
510 variable = self.parseDesignator()
|
|
|
511 if not variable.typ.isType(integer):
|
|
|
512 self.Error('loop variable of for statement must have integer type')
|
|
|
513 assert(variable.typ.isType(integer))
|
|
|
514 self.Consume(':=')
|
|
|
515 begin = self.parseExpression()
|
|
|
516 if not begin.typ.isType(integer):
|
|
|
517 self.Error('begin expression of a for statement must have integer type')
|
|
|
518 self.Consume('to')
|
|
|
519 end = self.parseExpression()
|
|
|
520 if not end.typ.isType(integer):
|
|
|
521 self.Error('end expression of a for statement must have integer type')
|
|
|
522 if self.hasConsumed('by'):
|
|
110
|
523 increment = self.parseConstant()
|
|
|
524 if not increment.typ.isType(integer):
|
|
100
|
525 self.Error('Increment must be integer')
|
|
110
|
526 increment = increment.value
|
|
100
|
527 else:
|
|
|
528 increment = 1
|
|
|
529 assert(type(increment) is int)
|
|
|
530 self.Consume('do')
|
|
|
531 statements = self.parseStatementSequence()
|
|
|
532 self.Consume('end')
|
|
|
533 return self.setLocation(ForStatement(variable, begin, end, increment, statements), loc)
|
|
70
|
534
|
|
100
|
535 def parseAsmcode(self):
|
|
|
536 # TODO: move this to seperate file
|
|
110
|
537 # TODO: determine what to do with inline asm?
|
|
100
|
538 def parseOpcode():
|
|
|
539 return self.Consume('ID')
|
|
|
540 def parseOperand():
|
|
|
541 if self.hasConsumed('['):
|
|
|
542 memref = []
|
|
|
543 memref.append(parseOperand())
|
|
|
544 self.Consume(']')
|
|
|
545 return memref
|
|
|
546 else:
|
|
|
547 if self.token.typ == 'NUMBER':
|
|
|
548 return self.Consume('NUMBER')
|
|
|
549 else:
|
|
|
550 ID = self.Consume('ID')
|
|
|
551 if self.cst.has(Variable, ID):
|
|
|
552 return self.cst.get(Variable, ID)
|
|
|
553 else:
|
|
|
554 return ID
|
|
|
555
|
|
|
556 def parseOperands(n):
|
|
|
557 operands = []
|
|
|
558 if n > 0:
|
|
|
559 operands.append( parseOperand() )
|
|
|
560 n = n - 1
|
|
|
561 while n > 0:
|
|
|
562 self.Consume(',')
|
|
|
563 operands.append(parseOperand())
|
|
|
564 n = n - 1
|
|
|
565 return operands
|
|
|
566 self.Consume('asm')
|
|
|
567 asmcode = []
|
|
|
568 while self.token.typ != 'end':
|
|
|
569 opcode = parseOpcode()
|
|
|
570 func, numargs = assembler.opcodes[opcode]
|
|
|
571 operands = parseOperands(numargs)
|
|
|
572 asmcode.append( (opcode, operands) )
|
|
|
573 #print('opcode', opcode, operands)
|
|
|
574 self.Consume('end')
|
|
|
575 return AsmCode(asmcode)
|
|
70
|
576
|
|
100
|
577 def parseStatement(self):
|
|
|
578 try:
|
|
|
579 # Determine statement type based on the pending token:
|
|
|
580 if self.token.typ == 'if':
|
|
|
581 return self.parseIfStatement()
|
|
|
582 elif self.token.typ == 'case':
|
|
|
583 return self.parseCaseStatement()
|
|
|
584 elif self.token.typ == 'while':
|
|
|
585 return self.parseWhileStatement()
|
|
|
586 elif self.token.typ == 'repeat':
|
|
|
587 return self.parseRepeatStatement()
|
|
|
588 elif self.token.typ == 'for':
|
|
|
589 return self.parseForStatement()
|
|
|
590 elif self.token.typ == 'asm':
|
|
|
591 return self.parseAsmcode()
|
|
|
592 elif self.token.typ == 'ID':
|
|
|
593 # Assignment or procedure call
|
|
|
594 designator = self.parseDesignator()
|
|
|
595 if self.token.typ == '(' and type(designator.typ) is ProcedureType:
|
|
|
596 return self.parseProcedureCall(designator)
|
|
|
597 elif self.token.typ == ':=':
|
|
|
598 return self.parseAssignment(designator)
|
|
|
599 else:
|
|
|
600 self.Error('Unknown statement following designator: {0}'.format(self.token))
|
|
|
601 else:
|
|
|
602 # TODO: return empty statement??:
|
|
|
603 return EmptyStatement()
|
|
|
604 self.Error('Unknown statement {0}'.format(self.token))
|
|
|
605 except CompilerException as e:
|
|
|
606 print(e)
|
|
|
607 self.errorlist.append( (e.row, e.col, e.msg))
|
|
|
608 # Do error recovery by skipping all tokens until next ; or end
|
|
|
609 while not (self.token.typ == ';' or self.token.typ == 'end'):
|
|
|
610 self.Consume(self.token.typ)
|
|
|
611 return EmptyStatement()
|
|
|
612
|
|
|
613 def parseStatementSequence(self):
|
|
|
614 """ Sequence of statements seperated by ';' """
|
|
110
|
615 statements = [self.parseStatement()]
|
|
100
|
616 while self.hasConsumed(';'):
|
|
110
|
617 statements.append(self.parseStatement())
|
|
|
618 return StatementSequence(statements)
|
|
70
|
619
|
|
|
620 # Parsing expressions:
|
|
|
621 """
|
|
|
622 grammar of expressions:
|
|
100
|
623 expression = SimpleExpression [ reloperator SimpleExpression ]
|
|
|
624 reloperator = '=' | '<=' | '>=' | '<>'
|
|
|
625 Simpleexpression = [ '+' | '-' ] term { addoperator term }
|
|
|
626 addoperator = '+' | '-' | 'or'
|
|
70
|
627 term = factor { muloperator factor }
|
|
100
|
628 muloperator = '*' | '/' | 'div' | 'mod' | 'and'
|
|
|
629 factor = number | nil | true | false | "(" expression ")" |
|
|
|
630 designator [ actualparameters ] | 'not' factor
|
|
70
|
631 """
|
|
110
|
632 def getTokenPrecedence(self):
|
|
|
633 binopPrecs = {}
|
|
|
634 binopPrecs['and'] = 8
|
|
|
635 binopPrecs['or'] = 6
|
|
|
636 binopPrecs['<'] = 10
|
|
|
637 binopPrecs['>'] = 10
|
|
|
638 binopPrecs['='] = 10
|
|
|
639 binopPrecs['<='] = 10
|
|
|
640 binopPrecs['>='] = 10
|
|
|
641 binopPrecs['<>'] = 10
|
|
|
642 binopPrecs['+'] = 20
|
|
|
643 binopPrecs['-'] = 20
|
|
|
644 binopPrecs['*'] = 40
|
|
|
645 binopPrecs['/'] = 40
|
|
|
646 binopPrecs['div'] = 40
|
|
|
647 binopPrecs['mod'] = 40
|
|
|
648
|
|
|
649 typ = self.token.typ
|
|
|
650 if typ in binopPrecs:
|
|
|
651 return binopPrecs[typ]
|
|
|
652 return 0
|
|
|
653 def parsePrimary(self):
|
|
|
654 pass
|
|
100
|
655 def parseExpression(self):
|
|
|
656 """ The connector between the boolean and expression domain """
|
|
110
|
657 # TODO: implement precedence bindin
|
|
|
658 #lhs = self.parsePrimary()
|
|
|
659 #return self.parseBinopRhs(lhs)
|
|
|
660
|
|
100
|
661 expr = self.parseSimpleExpression()
|
|
|
662 if self.token.typ in ['>=','<=','<','>','<>','=']:
|
|
|
663 relop = self.Consume()
|
|
|
664 expr2 = self.parseSimpleExpression()
|
|
|
665 # Automatic type convert to reals:
|
|
|
666 if isType(expr.typ, real) and isType(expr2.typ, integer):
|
|
|
667 expr2 = Unop(expr2, 'INTTOREAL', real)
|
|
|
668 if isType(expr2.typ, real) and isType(expr.typ, integer):
|
|
|
669 expr = Unop(expr, 'INTTOREAL', real)
|
|
|
670 # Type check:
|
|
|
671 if not isType(expr.typ, expr2.typ):
|
|
|
672 self.Error('Type mismatch in relop')
|
|
|
673 if isType(expr.typ, real) and relop in ['<>', '=']:
|
|
|
674 self.Error('Cannot check real values for equality')
|
|
|
675 expr = Relop(expr, relop, expr2, boolean)
|
|
|
676 return expr
|
|
70
|
677
|
|
|
678 # Parsing arithmatic expressions:
|
|
|
679 def parseTerm(self):
|
|
|
680 a = self.parseFactor()
|
|
|
681 while self.token.typ in ['*', '/', 'mod', 'div', 'and']:
|
|
|
682 loc = self.getLocation()
|
|
|
683 op = self.Consume()
|
|
|
684 b = self.parseTerm()
|
|
|
685 # Type determination and checking:
|
|
|
686 if op in ['mod', 'div']:
|
|
|
687 if not isType(a.typ, integer):
|
|
|
688 self.Error('First operand should be integer, not {0}'.format(a.typ))
|
|
|
689 if not isType(b.typ, integer):
|
|
|
690 self.Error('Second operand should be integer, not {0}'.format(b.typ))
|
|
|
691 typ = integer
|
|
|
692 elif op == '*':
|
|
|
693 if isType(a.typ, integer) and isType(b.typ, integer):
|
|
|
694 typ = integer
|
|
|
695 elif isType(a.typ, real) or isType(b.typ, real):
|
|
|
696 if isType(a.typ, integer):
|
|
|
697 # Automatic type cast
|
|
|
698 a = Unop(a, 'INTTOREAL', real)
|
|
|
699 if isType(b.typ, integer):
|
|
|
700 b = Unop(b, 'INTTOREAL', real)
|
|
|
701 if not isType(a.typ, real):
|
|
|
702 self.Error('first operand must be a real!')
|
|
|
703 if not isType(b.typ, real):
|
|
|
704 self.Error('second operand must be a real!')
|
|
|
705 typ = real
|
|
|
706 else:
|
|
|
707 self.Error('Unknown operands for multiply: {0}, {1}'.format(a, b))
|
|
|
708 elif op == '/':
|
|
|
709 # Division always yields a real result, for integer division use div
|
|
|
710 if isType(a.typ, integer):
|
|
|
711 # Automatic type cast
|
|
|
712 a = Unop(a, 'INTTOREAL', real)
|
|
|
713 if isType(b.typ, integer):
|
|
|
714 b = Unop(b, 'INTTOREAL', real)
|
|
|
715 if not isType(a.typ, real):
|
|
|
716 self.Error('first operand must be a real!')
|
|
|
717 if not isType(b.typ, real):
|
|
|
718 self.Error('second operand must be a real!')
|
|
|
719 typ = real
|
|
|
720 elif op == 'and':
|
|
|
721 if not isType(a.typ, boolean):
|
|
|
722 self.Error('First operand of and must be boolean')
|
|
|
723 if not isType(b.typ, boolean):
|
|
|
724 self.Error('Second operand of and must be boolean')
|
|
|
725 typ = boolean
|
|
|
726 else:
|
|
|
727 self.Error('Unknown operand {0}'.format(op))
|
|
|
728
|
|
|
729 a = self.setLocation(Binop(a, op, b, typ), loc)
|
|
|
730 return a
|
|
|
731
|
|
|
732 def parseFactor(self):
|
|
|
733 if self.hasConsumed('('):
|
|
|
734 e = self.parseExpression()
|
|
|
735 self.Consume(')')
|
|
|
736 return e
|
|
|
737 elif self.token.typ == 'NUMBER':
|
|
|
738 loc = self.getLocation()
|
|
|
739 val = self.Consume('NUMBER')
|
|
|
740 return self.setLocation(Constant(val, integer), loc)
|
|
|
741 elif self.token.typ == 'REAL':
|
|
|
742 loc = self.getLocation()
|
|
|
743 val = self.Consume('REAL')
|
|
|
744 return self.setLocation(Constant(val, real), loc)
|
|
|
745 elif self.token.typ == 'CHAR':
|
|
|
746 val = self.Consume('CHAR')
|
|
|
747 return Constant(val, char)
|
|
100
|
748 elif self.token.typ == 'STRING':
|
|
|
749 txt = self.Consume('STRING')
|
|
|
750 return StringConstant(txt)
|
|
110
|
751 elif self.hasConsumed('true'):
|
|
|
752 return Constant(True, boolean)
|
|
|
753 elif self.hasConsumed('false'):
|
|
|
754 return Constant(False, boolean)
|
|
70
|
755 elif self.hasConsumed('nil'):
|
|
|
756 return Constant(0, NilType())
|
|
|
757 elif self.hasConsumed('not'):
|
|
|
758 f = self.parseFactor()
|
|
|
759 if not isType(f.typ, boolean):
|
|
|
760 self.Error('argument of boolean negation must be boolean type')
|
|
|
761 return Unop(f, 'not', boolean)
|
|
|
762 elif self.token.typ == 'ID':
|
|
|
763 designator = self.parseDesignator()
|
|
|
764 # TODO: handle functions different here?
|
|
|
765 if self.token.typ == '(' and type(designator.typ) is ProcedureType:
|
|
|
766 return self.parseProcedureCall(designator)
|
|
|
767 else:
|
|
|
768 return designator
|
|
|
769 else:
|
|
|
770 self.Error('Expected NUMBER, ID or ( expr ), got'+str(self.token))
|
|
|
771
|
|
|
772 def parseSimpleExpression(self):
|
|
|
773 """ Arithmatic expression """
|
|
|
774 if self.token.typ in ['+', '-']:
|
|
|
775 # Handle the unary minus
|
|
|
776 op = self.Consume()
|
|
|
777 a = self.parseTerm()
|
|
|
778 typ = a.typ
|
|
|
779 if not isType(typ,real) and not isType(typ, integer):
|
|
|
780 self.Error('Unary minus or plus can be only applied to real or integers')
|
|
|
781 if op == '-':
|
|
|
782 a = Unop(a, op, typ)
|
|
|
783 else:
|
|
|
784 a = self.parseTerm()
|
|
|
785 while self.token.typ in ['+', '-', 'or']:
|
|
|
786 loc = self.getLocation()
|
|
|
787 op = self.Consume()
|
|
|
788 b = self.parseTerm()
|
|
|
789 if op in ['+', '-']:
|
|
|
790 if isType(a.typ, real) or isType(b.typ, real):
|
|
|
791 typ = real
|
|
|
792 if isType(a.typ, integer):
|
|
|
793 # Automatic type cast
|
|
|
794 a = Unop(a, 'INTTOREAL', real)
|
|
|
795 if not isType(a.typ, real):
|
|
|
796 self.Error('first operand must be a real!')
|
|
|
797 if isType(b.typ, integer):
|
|
|
798 b = Unop(b, 'INTTOREAL', real)
|
|
|
799 if not isType(b.typ, real):
|
|
|
800 self.Error('second operand must be a real!')
|
|
|
801 elif isType(a.typ, integer) and isType(b.typ, integer):
|
|
|
802 typ = integer
|
|
|
803 else:
|
|
|
804 self.Error('Invalid types {0} and {1}'.format(a.typ, b.typ))
|
|
|
805 elif op == 'or':
|
|
|
806 if not isType(a.typ, boolean):
|
|
|
807 self.Error('first operand must be boolean for or operation')
|
|
|
808 if not isType(b.typ, boolean):
|
|
|
809 self.Error('second operand must be boolean for or operation')
|
|
|
810 typ = boolean
|
|
|
811 else:
|
|
|
812 self.Error('Unknown operand {0}'.format(op))
|
|
|
813 a = self.setLocation(Binop(a, op, b, typ), loc)
|
|
|
814 return a
|
|
|
815
|
