--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/ppci/assembler.py	Thu Feb 13 22:02:08 2014 +0100
@@ -0,0 +1,203 @@
+
+import re
+import pyyacc
+from . import Token, CompilerError, SourceLocation
+from target import Target, Label
+from .asmnodes import ALabel, AInstruction, ABinop, AUnop, ASymbol, ANumber
+
+def tokenize(s):
+    """
+       Tokenizer, generates an iterator that
+       returns tokens!
+
+       This GREAT example was taken from python re doc page!
+    """
+    tok_spec = [
+       ('REAL', r'\d+\.\d+'),
+       ('HEXNUMBER', r'0x[\da-fA-F]+'),
+       ('NUMBER', r'\d+'),
+       ('ID', r'[A-Za-z][A-Za-z\d_]*'),
+       ('SKIP', r'[ \t]'),
+       ('LEESTEKEN', r':=|[\.,=:\-+*\[\]/\(\)]|>=|<=|<>|>|<|}|{'),
+       ('STRING', r"'.*?'"),
+       ('COMMENT', r";.*")
+    ]
+    tok_re = '|'.join('(?P<%s>%s)' % pair for pair in tok_spec)
+    gettok = re.compile(tok_re).match
+    line = 1
+    pos = line_start = 0
+    mo = gettok(s)
+    while mo is not None:
+       typ = mo.lastgroup
+       val = mo.group(typ)
+       if typ == 'NEWLINE':
+         line_start = pos
+         line += 1
+       elif typ != 'SKIP':
+         if typ == 'LEESTEKEN':
+           typ = val
+         elif typ == 'NUMBER':
+           val = int(val)
+         elif typ == 'HEXNUMBER':
+           val = int(val[2:], 16)
+           typ = 'NUMBER'
+         elif typ == 'REAL':
+           val = float(val)
+         elif typ == 'STRING':
+           val = val[1:-1]
+         col = mo.start() - line_start
+         loc = SourceLocation('', line, col, 0)   # TODO retrieve length?
+         yield Token(typ, val, loc)
+       pos = mo.end()
+       mo = gettok(s, pos)
+    if pos != len(s):
+       col = pos - line_start
+       loc = SourceLocation('', line, col, 0)
+       raise CompilerError('Unexpected character {0}'.format(s[pos]), loc)
+    yield Token('EOF', pyyacc.EOF)
+
+
+class Lexer:
+    def __init__(self, src):
+        self.tokens = tokenize(src)
+        self.curTok = self.tokens.__next__()
+
+    def next_token(self):
+        t = self.curTok
+        if t.typ != 'EOF':
+            self.curTok = self.tokens.__next__()
+        return t
+
+
+class Parser:
+    def __init__(self):
+        # Construct a parser given a grammar:
+        ident = lambda x: x   # Identity helper function
+        g = pyyacc.Grammar(['ID', 'NUMBER', ',', '[', ']', ':', '+', '-', '*', pyyacc.EPS, 'COMMENT', '{', '}',
+            pyyacc.EOF])
+        g.add_production('asmline', ['asmline2'])
+        g.add_production('asmline', ['asmline2', 'COMMENT'])
+        g.add_production('asmline2', ['label', 'instruction'])
+        g.add_production('asmline2', ['instruction'])
+        g.add_production('asmline2', ['label'])
+        g.add_production('asmline2', [])
+        g.add_production('label', ['ID', ':'], self.p_label)
+        #g.add_production('label', [])
+        g.add_production('instruction', ['opcode', 'operands'], self.p_ins_1)
+        g.add_production('instruction', ['opcode'], self.p_ins_2)
+        #g.add_production('instruction', [])
+        g.add_production('opcode', ['ID'], lambda x: x.val)
+        g.add_production('operands', ['operand'], self.p_operands_1)
+        g.add_production('operands', ['operands', ',', 'operand'], self.p_operands_2)
+        g.add_production('operand', ['expression'], ident)
+        g.add_production('operand', ['[', 'expression', ']'], self.p_mem_op)
+        g.add_production('operand', ['{', 'listitems', '}'], self.p_list_op)
+        g.add_production('listitems', ['expression'], self.p_listitems_1)
+        g.add_production('listitems', ['listitems', ',', 'expression'], self.p_listitems_2)
+        g.add_production('expression', ['term'], ident)
+        g.add_production('expression', ['expression', 'addop', 'term'], self.p_binop)
+        g.add_production('addop', ['-'], lambda x: x.val)
+        g.add_production('addop', ['+'], lambda x: x.val)
+        g.add_production('mulop', ['*'], lambda x: x.val)
+        g.add_production('term', ['factor'], ident)
+        g.add_production('term', ['term', 'mulop', 'factor'], self.p_binop)
+        g.add_production('factor', ['ID'], lambda name: ASymbol(name.val))
+        g.add_production('factor', ['NUMBER'], lambda num: ANumber(int(num.val)))
+        g.start_symbol = 'asmline'
+        self.p = g.genParser()
+
+    # Parser handlers:
+    def p_ins_1(self, opc, ops):
+        ins = AInstruction(opc, ops)
+        self.emit(ins)
+
+    def p_ins_2(self, opc):
+        self.p_ins_1(opc, [])
+
+    def p_operands_1(self, op1):
+        return [op1]
+
+    def p_operands_2(self, ops, comma, op2):
+        assert type(ops) is list
+        ops.append(op2)
+        return ops
+
+    def p_listitems_1(self, li1):
+        return [li1]
+
+    def p_listitems_2(self, lis, comma, li2):
+        assert type(lis) is list
+        lis.append(li2)
+        return lis
+
+    def p_list_op(self, brace_open, lst, brace_close):
+        return AUnop('{}', lst)
+
+    def p_mem_op(self, brace_open, exp, brace_close):
+        return AUnop('[]', exp)
+
+    def p_label(self, lname, cn):
+        lab = ALabel(lname.val)
+        self.emit(lab)
+
+    def p_binop(self, exp1, op, exp2):
+        return ABinop(op, exp1, exp2)
+
+    def parse(self, lexer, emitter):
+        self.emit = emitter
+        self.p.parse(lexer)
+
+# Pre construct parser to save time:
+asmParser = Parser()
+
+class Assembler:
+    def __init__(self, target=None, stream=None):
+        self.target = target
+        self.stream = stream
+        self.restart()
+        self.p = asmParser
+
+    # Top level interface:
+    def restart(self):
+        self.stack = []
+
+    def emit(self, a):
+        """ Emit a parsed instruction """
+        self.stack.append(a)
+
+    def parse_line(self, line):
+        """ Parse line into asm AST """
+        tokens = Lexer(line)
+        self.p.parse(tokens, self.emit)
+
+    def assemble(self, asmsrc):
+        """ Assemble this source snippet """
+        if type(asmsrc) is not str:
+            asmsrc2 = asmsrc.read()
+            asmsrc.close()
+            asmsrc = asmsrc2
+        for line in asmsrc.split('\n'):
+            self.assemble_line(line)
+
+    def assemble_line(self, line):
+        """
+            Assemble a single source line.
+            Do not take newlines into account
+        """
+        self.parse_line(line)
+        self.assemble_aast()
+
+    def assemble_aast(self):
+        """ Assemble a parsed asm line """
+        if not self.target:
+            raise CompilerError('Cannot assemble without target')
+        while self.stack:
+            vi = self.stack.pop(0)
+            if type(vi) is AInstruction:
+                mi = self.target.mapInstruction(vi)
+            elif type(vi) is ALabel:
+                mi = Label(vi.name)
+            else:
+                raise NotImplementedError('{}'.format(vi))
+            if self.stream:
+                self.stream.emit(mi)