Thanks for the link, but since it is using indention it doesn't cover what I wanted to do. It's the grammar that I'm not very good at. Any more help would be apreciated.
On Feb 10, 8:42 pm, Christian Wyglendowski <[email protected]> wrote: > Create tokens for the indentation/curly braces and the 'if' keyword > and then grammar rules that handle sequences of those tokens. I can't > go into too much more than that. The examples included with PLY cover > quite a bit, really. Have a look > athttp://www.juanjoconti.com.ar/files/python/ply-examples/GardenSnake/G... > for a partial implementation of Python called GardenSnake (including > the "if" statement). > > On Tue, Feb 10, 2009 at 3:33 PM, matio <[email protected]> wrote: > > > I meant how would I create an "if" statement, or anything that would > > need to be indented/in curly braces? > > Would I have to completely re-write the code or is there a way just to > > add it in as it is now (I've looked at the examples but it didn't seem > > to work)? > > > On Feb 9, 6:21 pm, matio <[email protected]> wrote: > >> How would I make something like an if? > > >> On Feb 8, 1:21 pm, David Beazley <[email protected]> wrote: > > >> > Either propagate values or don't print the result of the parse. > > >> > -Dave > > >> > On Sun 08/02/09 8:04 AM , matio [email protected] sent: > > >> > > how do I fix it? > > >> > > On Feb 8, 12:58 pm, David Beazley <[email protected] > >> > > om> wrote:> The calculator is printing the result of the > >> > > parse. It's printing> None because you're not propagating > >> > > values.> > >> > > > -Dave > > >> > > > On Sun 08/02/09 7:50 AM , matio ma...@hot > >> > > mail.co.uk sent:> > > >> > > > > what does that mean? > > >> > > > > On Feb 8, 12:18 pm, David Beazley > >> > > <[email protected]> > om> wrote:> You're not propagating > >> > > values correctly by> > assigning to p[0].> For example, in the > >> > > p_statement_expr()> > rule.> > >> > > > > > -Dave > > >> > > > > > On Sun 08/02/09 6:20 AM , matio > >> > > ma...@hot> > mail.co.uk sent:> > > >> > > > > > > I've been using ply & have > >> > > extended the> > example slightly:> > >> > > > > > > [code] > >> > > > > > > <code> > >> > > > > > > import ply.lex as lex > > >> > > > > > > reserved = {'print':'PRINT', > >> > > 'quit' :> > 'QUIT'}> > >> > > > > > > # List of token names. > >> > > This is> > always required> > tokens = > >> > > [> > > > 'NUMBER', > >> > > > > > > 'NAME', > >> > > > > > > 'PLUS', > >> > > > > > > 'MINUS', > >> > > > > > > 'TIMES', > >> > > > > > > 'DIVIDE', > >> > > > > > > 'LPAREN', > >> > > > > > > 'RPAREN', > >> > > > > > > 'EQUALS', > >> > > > > > > 'STRING', > >> > > > > > > ] + > >> > > list(reserved.values())> > >> > > > > > > # Regular expression rules for > >> > > simple> > tokens> > t_PLUS = > >> > > r'\+'> > > > t_MINUS = r'-' > >> > > > > > > t_TIMES = r'\*' > >> > > > > > > t_DIVIDE = r'/' > >> > > > > > > t_LPAREN = r'\(' > >> > > > > > > t_RPAREN = r'\)' > >> > > > > > > t_EQUALS = r'=' > > >> > > > > > > def t_NAME(t): > > >> > > r'[a-zA-Z_][a-zA-Z_0-9]*'> > > > t.type = > >> > > reserved.get(t.value,'NAME')> > # Check for reserved> > > >> > > words> > > > return t > > >> > > > > > > # A regular expression rule with > >> > > some> > action code> > def > >> > > t_NUMBER(t):> > > > r'\d+' > >> > > > > > > t.value = int(t.value) > >> > > > > > > return t > > >> > > > > > > # Define a rule so we can track > >> > > line> > numbers> > def > >> > > t_newline(t):> > > > r'\n+' > >> > > > > > > t.lexer.lineno += > >> > > len(t.value)> > >> > > > > > > def t_STRING(t): > > >> > > > > r'\"([^\\"]|(\\.))*\"'> > >> > > > escaped = 0> > > > str = t.value[1:-1] > >> > > > > > > new_str = "" > >> > > > > > > for i in range(0, > >> > > len(str)):> > > > c = str[i] > >> > > > > > > if escaped: > >> > > > > > > if c == "n": > >> > > > > > > c = "\n" > >> > > > > > > elif c == > >> > > "t":> > > > c = "\t" > >> > > > > > > new_str += c > >> > > > > > > escaped = 0 > >> > > > > > > else: > >> > > > > > > if c == > >> > > "\\":> > > > escaped = 1 > >> > > > > > > else: > >> > > > > > > new_str += c > >> > > > > > > t.value = new_str > >> > > > > > > return t > > >> > > > > > > # A string containing ignored > >> > > characters> > (spaces and tabs)> > t_ignore = > >> > > ' \t'> > >> > > > > > > # Error handling rule > >> > > > > > > def t_error(t): > >> > > > > > > print "Illegal character > >> > > '%s'" %> > t.value[0]> > > >> > > t.lexer.skip(1)> > >> > > > > > > # Build the lexer > >> > > > > > > lexer = lex.lex() > >> > > > > > > [/code] > >> > > > > > > </code> > > >> > > > > > > & > > >> > > > > > > [code] > >> > > > > > > <code> > >> > > > > > > import ply.yacc as > >> > > yacc> > > > import sys > > >> > > > > > > # Get the token map from the > >> > > lexer.> > This is required.> > from > >> > > calclex import tokens> > >> > > > > > > names = {} > >> > > > > > > def > >> > > p_statement_assign(t):> > > > 'statement : NAME > >> > > EQUALS> > expression'> > names[t[1]] = > >> > > t[3]> > >> > > > > > > def > >> > > p_statement_expr(t):> > > > 'statement : > >> > > expression'> > > > if t[1] != None: > >> > > > > > > print t[1] > >> > > > > > > else: > >> > > > > > > pass > > >> > > > > > > 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_expression_plus(p):> > > > 'expression : expression > >> > > PLUS> > term'> > p[0] = p[1] + > >> > > p[3]> > >> > > > > > > def > >> > > p_expression_minus(p):> > > > 'expression : expression > >> > > MINUS> > term'> > p[0] = p[1] - > >> > > p[3]> > >> > > > > > > def > >> > > p_expression_term(p):> > > > 'expression : term' > >> > > > > > > p[0] = p[1] > > >> > > > > > > def p_term_times(p): > >> > > > > > > 'term : term TIMES > >> > > factor'> > > > p[0] = p[1] * p[3] > > >> > > > > > > def p_term_div(p): > >> > > > > > > 'term : term DIVIDE > >> > > factor'> > > > p[0] = p[1] / p[3] > > >> > > > > > > def p_term_factor(p): > >> > > > > > > 'term : factor' > >> > > > > > > p[0] = p[1] > > >> > > > > > > def p_factor_num(p): > >> > > > > > > 'factor : NUMBER' > >> > > > > > > p[0] = p[1] > > >> > > > > > > def p_factor_expr(p): > >> > > > > > > 'factor : LPAREN > >> > > expression> > RPAREN'> > p[0] = p[2] > > >> > > > > > > def p_print(p): > >> > > > > > > '''expression : PRINT LPAREN > >> > > STRING> > RPAREN> > | PRINT LPAREN > >> > > expression> > RPAREN'''> > p[0] = p[3] > > >> > > > > > > def p_quit(p): > >> > > > > > > 'expression : QUIT' > >> > > > > > > sys.exit() > > >> > > > > > > # Error rule for syntax > >> > > errors> > > > def p_error(p): > >> > > > > > > print "Syntax error > >> > > in> > input!"> > >> > > > > > > # Build the parser > >> > > > > > > parser = yacc.yacc() > > >> > > > > > > if len(sys.argv) == 1: > >> > > > > > > while True: > >> > > > > > > try: > >> > > > > > > s = raw_input('calc > > >> > > ')> > > > except EOFError: > >> > > > > > > break > >> > > > > > > if not s: continue > >> > > > > > > result = > >> > > parser.parse(s)> > > > print result > > >> > > > > > > elif sys.argv[1] == > >> > > > > "-f":> > f = > >> > > open(sys.argv[2],> > "r")> > s = > >> > > f.readlines()> > > > for line in s: > >> > > > > > > result = > >> > > parser.parse(line)> > > > if result != None: > >> > > > > > > print "result != > >> > > none"> > > > print result > >> > > > > > > [/code] > >> > > > > > > </code> > >> > > > > > > When I run > >> > > print("hello") it> > says:> > hello > >> > > > > > > none > >> > > > > > > calc> > > >> > > > > > > What's wrong? > >> > > > > > > I also posted it > >> > > > > > > athttp://ubuntuforums.org/showthread.php?p=6698006#post6698006&; > >> > > amp;> > gt;> --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "ply-hack" group. 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