source: proto/matchparens/parenmatch2.py @ 5735

Last change on this file since 5735 was 3064, checked in by cameron, 6 years ago

Simplify parenthesis matching; fix paren match with comments.

File size: 2.0 KB
Line 
1#
2# Recursive Parenthesis Matching
3#
4#
5# Robert D. Cameron
6# October 14, 2012
7#
8import sys
9import pablo
10
11class Basis_bits():     
12        bit_0 = 0
13        bit_1 = 0
14        bit_2 = 0
15        bit_3 = 0
16        bit_4 = 0
17        bit_5 = 0
18        bit_6 = 0
19        bit_7 = 0
20
21class Lex ():
22        LParen = 0
23        RParen = 0
24       
25class Matches() :
26        closed = 0
27        error = 0
28
29
30def Classify_bytes(basis_bits, lex): 
31        temp1 = (basis_bits.bit_0 | basis_bits.bit_1)
32        temp2 = (basis_bits.bit_2 &~ basis_bits.bit_3)
33        temp3 = (temp2 &~ temp1)
34        temp4 = (basis_bits.bit_4 &~ basis_bits.bit_5)
35        temp5 = (basis_bits.bit_6 | basis_bits.bit_7)
36        temp6 = (temp4 &~ temp5)
37        lex.LParen = (temp3 & temp6)
38        temp7 = (basis_bits.bit_7 &~ basis_bits.bit_6)
39        temp8 = (temp4 & temp7)
40        lex.RParen = (temp3 & temp8)
41       
42def Match_Parens(lex, matches):
43        parens = lex.LParen | lex.RParen
44        pscan = pablo.AdvanceThenScanTo(lex.LParen, parens)
45        matches.closed = pscan & lex.RParen
46        matches.error = pablo.atEOF(pscan)
47        # Not matched, still pending.
48        pending_LParen = pscan & lex.LParen
49        RParen_unmatched = lex.RParen &~ matches.closed
50        inPlay = pending_LParen | RParen_unmatched
51        while pending_LParen:
52                pscan = pablo.AdvanceThenScanTo(pending_LParen, inPlay)
53                matches.closed |= pscan & lex.RParen
54                matches.error |= pablo.atEOF(pscan)
55                pending_LParen = pscan & lex.LParen
56                RParen_unmatched = lex.RParen &~ matches.closed
57                inPlay = pending_LParen | RParen_unmatched
58        #
59        # Any closing paren that was not actually used to close
60        # an opener is in error.
61        matches.error |= lex.RParen &~ matches.closed
62
63basis_bits = Basis_bits()
64lex = Lex()
65matches = Matches()
66
67if __name__ == "__main__":
68        #print "Starting ..."
69        if len(sys.argv) > 1:
70                u8data = pablo.readfile(sys.argv[1]) 
71                pablo.EOF_mask = pablo.transpose_streams(u8data, basis_bits)
72                Classify_bytes(basis_bits, lex)
73                Match_Parens(lex, matches)
74                lgth = len(u8data)
75                print "data:" + " "*(16-5) + u8data
76                print "errors" + " "*(16-6) + pablo.bitstream2string(matches.error, lgth+1)
77               
78        else:
79                print("Usage: python parenmatch.py <file>")
80       
81
82
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