cscg24-lolpython

CSCG 2024 Challenge 'Can I Haz Lolpython?'
git clone https://git.sinitax.com/sinitax/cscg24-lolpython
Log | Files | Refs | sfeed.txt

yacc_badtok.py (1531B)

      1# -----------------------------------------------------------------------------
      2# yacc_badtok.py
      3#
      4# A grammar, but tokens is a bad datatype
      5# -----------------------------------------------------------------------------
      6
      7import sys
      8sys.tracebacklimit = 0
      9
     10sys.path.insert(0,"..")
     11import ply.yacc as yacc
     12
     13tokens = "Hello"
     14
     15# Parsing rules
     16precedence = (
     17    ('left','PLUS','MINUS'),
     18    ('left','TIMES','DIVIDE'),
     19    ('right','UMINUS'),
     20    )
     21
     22# dictionary of names
     23names = { }
     24
     25def p_statement_assign(t):
     26    'statement : NAME EQUALS expression'
     27    names[t[1]] = t[3]
     28
     29def p_statement_expr(t):
     30    'statement : expression'
     31    print t[1]
     32
     33def p_expression_binop(t):
     34    '''expression : expression PLUS expression
     35                  | expression MINUS expression
     36                  | expression TIMES expression
     37                  | expression DIVIDE expression'''
     38    if t[2] == '+'  : t[0] = t[1] + t[3]
     39    elif t[2] == '-': t[0] = t[1] - t[3]
     40    elif t[2] == '*': t[0] = t[1] * t[3]
     41    elif t[3] == '/': t[0] = t[1] / t[3]
     42
     43def p_expression_uminus(t):
     44    'expression : MINUS expression %prec UMINUS'
     45    t[0] = -t[2]
     46
     47def p_expression_group(t):
     48    'expression : LPAREN expression RPAREN'
     49    t[0] = t[2]
     50
     51def p_expression_number(t):
     52    'expression : NUMBER'
     53    t[0] = t[1]
     54
     55def p_expression_name(t):
     56    'expression : NAME'
     57    try:
     58        t[0] = names[t[1]]
     59    except LookupError:
     60        print "Undefined name '%s'" % t[1]
     61        t[0] = 0
     62
     63def p_error(t):
     64    print "Syntax error at '%s'" % t.value
     65
     66yacc.yacc()
     67
     68
     69
     70