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Fixed formatting

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dabeaz committed May 29, 2013
1 parent 2d135fa commit dc32f83b78ce824987bece64759cd2830a928fae
Showing with 103 additions and 103 deletions.
  1. +103 −103 README.md
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206 README.md
@@ -141,109 +141,109 @@ Example
Here is a simple example showing a PLY implementation of a calculator
with variables.
-# -----------------------------------------------------------------------------
-# calc.py
-#
-# A simple calculator with variables.
-# -----------------------------------------------------------------------------
-
-tokens = (
- 'NAME','NUMBER',
- 'PLUS','MINUS','TIMES','DIVIDE','EQUALS',
- 'LPAREN','RPAREN',
- )
-
-# Tokens
-
-t_PLUS = r'\+'
-t_MINUS = r'-'
-t_TIMES = r'\*'
-t_DIVIDE = r'/'
-t_EQUALS = r'='
-t_LPAREN = r'\('
-t_RPAREN = r'\)'
-t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*'
-
-def t_NUMBER(t):
- r'\d+'
- t.value = int(t.value)
- return t
-
-# Ignored characters
-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()
-
-# Precedence rules for the arithmetic operators
-precedence = (
- ('left','PLUS','MINUS'),
- ('left','TIMES','DIVIDE'),
- ('right','UMINUS'),
- )
-
-# dictionary of names (for storing variables)
-names = { }
-
-def p_statement_assign(p):
- 'statement : NAME EQUALS expression'
- names[p[1]] = p[3]
-
-def p_statement_expr(p):
- 'statement : expression'
- print(p[1])
-
-def p_expression_binop(p):
- '''expression : expression PLUS expression
- | expression MINUS expression
- | expression TIMES expression
- | expression DIVIDE 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]
-
-def p_expression_uminus(p):
- 'expression : MINUS expression %prec UMINUS'
- p[0] = -p[2]
-
-def p_expression_group(p):
- 'expression : LPAREN expression RPAREN'
- p[0] = p[2]
-
-def p_expression_number(p):
- 'expression : NUMBER'
- p[0] = p[1]
-
-def p_expression_name(p):
- 'expression : NAME'
- try:
- p[0] = names[p[1]]
- except LookupError:
- print("Undefined name '%s'" % p[1])
- p[0] = 0
-
-def p_error(p):
- print("Syntax error at '%s'" % p.value)
-
-import ply.yacc as yacc
-yacc.yacc()
-
-while 1:
- try:
- s = raw_input('calc > ') # use input() on Python 3
- except EOFError:
- break
- yacc.parse(s)
+ # -----------------------------------------------------------------------------
+ # calc.py
+ #
+ # A simple calculator with variables.
+ # -----------------------------------------------------------------------------
+
+ tokens = (
+ 'NAME','NUMBER',
+ 'PLUS','MINUS','TIMES','DIVIDE','EQUALS',
+ 'LPAREN','RPAREN',
+ )
+
+ # Tokens
+
+ t_PLUS = r'\+'
+ t_MINUS = r'-'
+ t_TIMES = r'\*'
+ t_DIVIDE = r'/'
+ t_EQUALS = r'='
+ t_LPAREN = r'\('
+ t_RPAREN = r'\)'
+ t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*'
+
+ def t_NUMBER(t):
+ r'\d+'
+ t.value = int(t.value)
+ return t
+
+ # Ignored characters
+ 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()
+
+ # Precedence rules for the arithmetic operators
+ precedence = (
+ ('left','PLUS','MINUS'),
+ ('left','TIMES','DIVIDE'),
+ ('right','UMINUS'),
+ )
+
+ # dictionary of names (for storing variables)
+ names = { }
+
+ def p_statement_assign(p):
+ 'statement : NAME EQUALS expression'
+ names[p[1]] = p[3]
+
+ def p_statement_expr(p):
+ 'statement : expression'
+ print(p[1])
+
+ def p_expression_binop(p):
+ '''expression : expression PLUS expression
+ | expression MINUS expression
+ | expression TIMES expression
+ | expression DIVIDE 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]
+
+ def p_expression_uminus(p):
+ 'expression : MINUS expression %prec UMINUS'
+ p[0] = -p[2]
+
+ def p_expression_group(p):
+ 'expression : LPAREN expression RPAREN'
+ p[0] = p[2]
+
+ def p_expression_number(p):
+ 'expression : NUMBER'
+ p[0] = p[1]
+
+ def p_expression_name(p):
+ 'expression : NAME'
+ try:
+ p[0] = names[p[1]]
+ except LookupError:
+ print("Undefined name '%s'" % p[1])
+ p[0] = 0
+
+ def p_error(p):
+ print("Syntax error at '%s'" % p.value)
+
+ import ply.yacc as yacc
+ yacc.yacc()
+
+ while 1:
+ try:
+ s = raw_input('calc > ') # use input() on Python 3
+ except EOFError:
+ break
+ yacc.parse(s)
Bug Reports and Patches

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