Mercurial > repo
diff ply-3.8/test/yacc_error6.py @ 7267:343ff337a19b
<ais523> ` tar -xf ply-3.8.tar.gz
author | HackBot |
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date | Wed, 23 Mar 2016 02:40:16 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/ply-3.8/test/yacc_error6.py Wed Mar 23 02:40:16 2016 +0000 @@ -0,0 +1,80 @@ +# ----------------------------------------------------------------------------- +# yacc_error6.py +# +# Panic mode recovery test +# ----------------------------------------------------------------------------- +import sys + +if ".." not in sys.path: sys.path.insert(0,"..") +import ply.yacc as yacc + +from calclex import tokens + +# Parsing rules +precedence = ( + ('left','PLUS','MINUS'), + ('left','TIMES','DIVIDE'), + ('right','UMINUS'), + ) + +def p_statements(t): + 'statements : statements statement' + pass + +def p_statements_1(t): + 'statements : statement' + pass + +def p_statement_assign(p): + 'statement : LPAREN NAME EQUALS expression RPAREN' + print("%s=%s" % (p[2],p[4])) + +def p_statement_expr(t): + 'statement : LPAREN expression RPAREN' + print(t[1]) + +def p_expression_binop(t): + '''expression : expression PLUS expression + | expression MINUS expression + | expression TIMES expression + | expression DIVIDE expression''' + if t[2] == '+' : t[0] = t[1] + t[3] + elif t[2] == '-': t[0] = t[1] - t[3] + elif t[2] == '*': t[0] = t[1] * t[3] + elif t[2] == '/': t[0] = t[1] / t[3] + +def p_expression_uminus(t): + 'expression : MINUS expression %prec UMINUS' + t[0] = -t[2] + +def p_expression_number(t): + 'expression : NUMBER' + t[0] = t[1] + +def p_error(p): + if p: + print("Line %d: Syntax error at '%s'" % (p.lineno, p.value)) + # Scan ahead looking for a name token + while True: + tok = parser.token() + if not tok or tok.type == 'RPAREN': + break + if tok: + parser.restart() + return None + +parser = yacc.yacc() +import calclex +calclex.lexer.lineno=1 + +parser.parse(""" +(a = 3 + 4) +(b = 4 + * 5 - 6 + *) +(c = 10 + 11) +""") + + + + + +