diff options
Diffstat (limited to 'example/calcdebug/calc.py')
| -rw-r--r-- | example/calcdebug/calc.py | 52 |
1 files changed, 34 insertions, 18 deletions
diff --git a/example/calcdebug/calc.py b/example/calcdebug/calc.py index 6732f9f..06831e2 100644 --- a/example/calcdebug/calc.py +++ b/example/calcdebug/calc.py @@ -6,20 +6,21 @@ # ----------------------------------------------------------------------------- import sys -sys.path.insert(0,"../..") +sys.path.insert(0, "../..") if sys.version_info[0] >= 3: raw_input = input tokens = ( - 'NAME','NUMBER', - ) + 'NAME', 'NUMBER', +) -literals = ['=','+','-','*','/', '(',')'] +literals = ['=', '+', '-', '*', '/', '(', ')'] # Tokens -t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*' +t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*' + def t_NUMBER(t): r'\d+' @@ -28,14 +29,16 @@ def t_NUMBER(t): t_ignore = " \t" + def t_newline(t): r'\n+' t.lexer.lineno += t.value.count("\n") - + + def t_error(t): print("Illegal character '%s'" % t.value[0]) t.lexer.skip(1) - + # Build the lexer import ply.lex as lex lex.lex() @@ -43,44 +46,55 @@ lex.lex() # Parsing rules precedence = ( - ('left','+','-'), - ('left','*','/'), - ('right','UMINUS'), - ) + ('left', '+', '-'), + ('left', '*', '/'), + ('right', 'UMINUS'), +) # dictionary of names -names = { } +names = {} + def p_statement_assign(p): 'statement : NAME "=" expression' names[p[1]] = p[3] + def p_statement_expr(p): 'statement : expression' print(p[1]) + def p_expression_binop(p): '''expression : expression '+' expression | expression '-' expression | expression '*' expression | expression '/' expression''' - if p[2] == '+' : p[0] = p[1] + p[3] - elif p[2] == '-': p[0] = p[1] - p[3] - elif p[2] == '*': p[0] = p[1] * p[3] - elif p[2] == '/': p[0] = p[1] / p[3] + if p[2] == '+': + p[0] = p[1] + p[3] + elif p[2] == '-': + p[0] = p[1] - p[3] + elif p[2] == '*': + p[0] = p[1] * p[3] + elif p[2] == '/': + p[0] = p[1] / p[3] + def p_expression_uminus(p): "expression : '-' expression %prec UMINUS" p[0] = -p[2] + def p_expression_group(p): "expression : '(' expression ')'" p[0] = p[2] + def p_expression_number(p): "expression : NUMBER" p[0] = p[1] + def p_expression_name(p): "expression : NAME" try: @@ -89,6 +103,7 @@ def p_expression_name(p): print("Undefined name '%s'" % p[1]) p[0] = 0 + def p_error(p): if p: print("Syntax error at '%s'" % p.value) @@ -109,5 +124,6 @@ while 1: s = raw_input('calc > ') except EOFError: break - if not s: continue - yacc.parse(s,debug=logging.getLogger()) + if not s: + continue + yacc.parse(s, debug=logging.getLogger()) |