diff options
| -rwxr-xr-x | parsertest.py | 93 |
1 files changed, 79 insertions, 14 deletions
diff --git a/parsertest.py b/parsertest.py index 12e97ee..0bb9710 100755 --- a/parsertest.py +++ b/parsertest.py @@ -99,10 +99,28 @@ class Lexer: line_start = loc if par_count > 0 or bracket_count > 0: break + elif tid == 'id': + if match_text in self.keywords: + tid = match_text yield Token(tid, curline, col) if not matched: raise ParseException('lexer', lineno, col) +# Recursive descent parser for Meson's definition language. +# Very basic apart from the fact that we have many precedence +# levels so there are not enough words to describe them all. +# Enter numbering: +# +# 1 assignment +# 2 or +# 3 and +# 4 equality +# comparison, plus and multiplication would go here +# 5 negation +# 6 funcall, method call +# 7 parentheses +# 8 plain token + class Parser: def __init__(self, code): self.stream = Lexer().lex(code) @@ -120,20 +138,68 @@ class Parser: def expect(self, s): if self.accept(s): return True - raise ParseException('Unknown token', self.current.lineno, self.current.colno) + raise ParseException('Unknown token ' + self.current.tid, self.current.lineno, self.current.colno) def parse(self): self.codeblock() def statement(self): - if self.accept('lparen'): - self.statement() - self.expect('rparen') - if self.accept('lbracket'): + self.e1() + + def e1(self): + self.e2() + while self.accept('assign'): + self.e1() + + def e2(self): + self.e3() + if self.accept('or'): + self.e3() + + def e3(self): + self.e4() + if self.accept('and'): + self.e4() + + def e4(self): + self.e5() + if self.accept('equal'): + self.e5() + + def e5(self): + if self.accept('not'): + pass + self.e6() + + def e6(self): + self.e7() + if self.accept('dot'): + self.method_call() + self.e6() + elif self.accept('lparen'): self.args() - self.expect('rbracket') - self.expression() - self.rest_statement() + self.expect('rparen') + self.e6() + + def e7(self): + if self.accept('('): + self.expression() + self.expect(')') + else: + self.e8() + + def e8(self): + #t = self.current + if self.accept('true'): + return + if self.accept('false'): + return + if self.accept('id'): + return + if self.accept('number'): + return + if self.accept('string'): + return def args(self): self.statement() @@ -149,7 +215,7 @@ class Parser: self.method_call() def method_call(self): - self.expression() + self.e8() self.expect('lparen') self.args() self.expect('rparen') @@ -177,19 +243,20 @@ class Parser: self.expect('rparen') def ifelseblock(self): - if self.current == 'elif': + if self.accept('elif'): self.statement() self.expect('eol') self.codeblock() def elseblock(self): - if self.current == 'else': + if self.accept('else'): self.expect('eol') self.codeblock() def line(self): if self.accept('if'): self.statement() + self.codeblock() self.ifelseblock() self.elseblock() self.expect('endif') @@ -198,12 +265,10 @@ class Parser: self.statement() def codeblock(self): - if self.accept('eol'): - return self.codeblock() cond = True while cond: self.line() - cond = self.expect('eol') + cond = self.expect('eol') or self.current == 'elif' or self.current == 'else' if __name__ == '__main__': code = open(sys.argv[1]).read() |