1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
|
PT
NAME
pt - canonical LR(1) parse (action and goto) table generator.
The input grammar productions with added enumerations,
needed as part of the reduction in the action
table, is also part of the output.
(Various optional outputs are possible:-
terminal sets
nonterminal sets
first sets for nonterminals
items in each state)
SYNOPSIS
pt [ option | option | ... ]
DESCRIPTION
Pt reads the grammar from the file called grammar, if one exists,
else it will read from standard input. The grammar MUST conform
to the following:-
1. It must be a context-free grammar, augmented or unaugmented.
2. Each production is of the form:-
A -> B ; C a
The arrow separates the left side of the production
from the right side.
The left side of the production consists of only one
nonterminal.
The right side of the production consists of a sequence
of symbols (terminals, nonterminals) with one or
more white spaces (blanks and tabs) separating them.
A symbol is thus either a terminal or a nonterminal but
not both.
3. One production per line; no alternation allowed. Thus,
represent the following 2 productions:-
A -> B ; C a | b
by:-
A -> B ; C a
A -> b
4. Newline character, tab and blank cannot be a grammar token
(terminal or nonterminal).
5. The left hand side symbol of the very first production
represents the starting symbol of the grammar.
6. The following are "reserved" words:-
START
EOI
and cannot be used as a terminal or nonterminal.
7. EPSILON is considered another "reserved" word and can be
used to represent an empty production, viz.
H -> EPSILON
No error messages will be issued if the input grammar does not
conform to the above specifications.
The options, which can appear in any order, are:-
-t Print the list of terminals in the grammar.
-nt Print the list of nonterminals in the grammar.
-f Print the list of first sets of the nonterminals
in the grammar.
-e Print the list of items (i.e. closure) in each state.
FILES
grammar grammar file with format specified above.
SEE ALSO
yacc
Aho A.V., Sethi, R. and Ullman, J.D., Compilers: Principles,
Techniques, and Tools. Addison-Wesley, 1986.
DIAGNOSTICS
All shift/reduce conflicts will be reported (to errout). In the
table form, only shift will be shown.
To avoid reduce/reduce conflict the grammar should be unambiguous
with left-factoring performed if necessary.
Unrecognized options or arguments in the command line will be
ignored.
BUGS
No known bugs!
AUTHOR
Deeporn H. Beardsley
|
