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Diffstat (limited to 'ext/ply/test/yacc_missing1.py')
-rw-r--r-- | ext/ply/test/yacc_missing1.py | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/ext/ply/test/yacc_missing1.py b/ext/ply/test/yacc_missing1.py new file mode 100644 index 000000000..e63904d0e --- /dev/null +++ b/ext/ply/test/yacc_missing1.py @@ -0,0 +1,67 @@ +# ----------------------------------------------------------------------------- +# yacc_missing1.py +# +# Grammar with a missing rule +# ----------------------------------------------------------------------------- +import sys +sys.tracebacklimit = 0 + +from calclex import tokens + +# Parsing rules +precedence = ( + ('left','PLUS','MINUS'), + ('left','TIMES','DIVIDE'), + ('right','UMINUS'), + ) + +# dictionary of names +names = { } + +def p_statement_assign(t): + 'statement : location EQUALS expression' + names[t[1]] = t[3] + +def p_statement_expr(t): + 'statement : expression' + 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[3] == '/': t[0] = t[1] / t[3] + +def p_expression_uminus(t): + 'expression : MINUS expression %prec UMINUS' + t[0] = -t[2] + +def p_expression_group(t): + 'expression : LPAREN expression RPAREN' + t[0] = t[2] + +def p_expression_number(t): + 'expression : NUMBER' + t[0] = t[1] + +def p_expression_name(t): + 'expression : NAME' + try: + t[0] = names[t[1]] + except LookupError: + print "Undefined name '%s'" % t[1] + t[0] = 0 + +def p_error(t): + print "Syntax error at '%s'" % t.value + +import yacc +yacc.yacc() + + + + |