calclex.py

来自「linux下基于c++的处理器仿真平台。具有处理器流水线」· Python 代码 · 共 47 行

# -----------------------------------------------------------------------------
# calclex.py
# -----------------------------------------------------------------------------

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+'
    try:
        t.value = int(t.value)
    except ValueError:
        print "Integer value too large", t.value
        t.value = 0
    return t

t_ignore = " \t"

def t_newline(t):
    r'\n+'
    t.lineno += t.value.count("\n")
    
def t_error(t):
    print "Illegal character '%s'" % t.value[0]
    t.skip(1)
    
# Build the lexer
import lex
lex.lex()