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1 | (* bnflex.def provides a simple lexical package for pg. |
2 | ||
83ffe9cd | 3 | Copyright (C) 2001-2023 Free Software Foundation, Inc. |
1eee94d3 GM |
4 | Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>. |
5 | ||
6 | This file is part of GNU Modula-2. | |
7 | ||
8 | GNU Modula-2 is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 3, or (at your option) | |
11 | any later version. | |
12 | ||
13 | GNU Modula-2 is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with GNU Modula-2; see the file COPYING3. If not see | |
20 | <http://www.gnu.org/licenses/>. *) | |
21 | ||
22 | DEFINITION MODULE bnflex ; | |
23 | ||
24 | (* | |
25 | Title : bnflex | |
26 | Author : Gaius Mulley | |
27 | System : UNIX (gm2) | |
28 | Date : Mon Sep 13 08:53:02 1999 | |
29 | Last edit : Mon Sep 13 08:53:02 1999 | |
30 | Description: provides a simple lexical package for pg. | |
31 | *) | |
32 | ||
33 | FROM NameKey IMPORT Name ; | |
34 | EXPORT QUALIFIED IsSym, SymIs, TokenType, GetCurrentTokenType, GetCurrentToken, | |
35 | GetChar, PutChar, OpenSource, CloseSource, | |
36 | SkipUntilWhite, SkipWhite, SkipUntilEoln, AdvanceToken, IsReserved, PushBackToken, | |
37 | SetDebugging ; | |
38 | ||
39 | TYPE | |
40 | TokenType = (identtok, literaltok, codetok, lbecomestok, rbecomestok, bartok, lsparatok, rsparatok, | |
41 | lcparatok, rcparatok, lparatok, rparatok, errortok, tfunctok, symfunctok, | |
42 | squotetok, dquotetok, moduletok, begintok, rulestok, endtok, lesstok, gretok, | |
43 | tokentok, specialtok, firsttok, followtok, BNFtok, FNBtok, declarationtok, | |
44 | epsilontok, eoftok) ; | |
45 | ||
46 | ||
47 | (* | |
48 | OpenSource - Attempts to open the source file, a. | |
49 | The success of the operation is returned. | |
50 | *) | |
51 | ||
52 | PROCEDURE OpenSource (a: ARRAY OF CHAR) : BOOLEAN ; | |
53 | ||
54 | ||
55 | (* | |
56 | CloseSource - Closes the current open file. | |
57 | *) | |
58 | ||
59 | PROCEDURE CloseSource ; | |
60 | ||
61 | ||
62 | (* | |
63 | GetChar - returns the current character on the input stream. | |
64 | *) | |
65 | ||
66 | PROCEDURE GetChar () : CHAR ; | |
67 | ||
68 | ||
69 | (* | |
70 | PutChar - pushes a character onto the push back stack, it also | |
71 | returns the character which has been pushed. | |
72 | *) | |
73 | ||
74 | PROCEDURE PutChar (ch: CHAR) : CHAR ; | |
75 | ||
76 | ||
77 | (* | |
78 | SymIs - if t is equal to the current token the next token is read | |
79 | and true is returned, otherwise false is returned. | |
80 | *) | |
81 | ||
82 | PROCEDURE SymIs (t: TokenType) : BOOLEAN ; | |
83 | ||
84 | ||
85 | (* | |
86 | IsSym - returns the result of the comparison between the current token | |
87 | type and t. | |
88 | *) | |
89 | ||
90 | PROCEDURE IsSym (t: TokenType) : BOOLEAN ; | |
91 | ||
92 | ||
93 | (* | |
94 | GetCurrentTokenType - returns the type of current token. | |
95 | *) | |
96 | ||
97 | PROCEDURE GetCurrentTokenType () : TokenType ; | |
98 | ||
99 | ||
100 | (* | |
101 | GetCurrentToken - returns the NameKey of the current token. | |
102 | *) | |
103 | ||
104 | PROCEDURE GetCurrentToken () : Name ; | |
105 | ||
106 | ||
107 | (* | |
108 | SkipUntilWhite - skips all characters until white space is seen. | |
109 | *) | |
110 | ||
111 | PROCEDURE SkipUntilWhite ; | |
112 | ||
113 | ||
114 | (* | |
115 | SkipWhite - skips all white space. | |
116 | *) | |
117 | ||
118 | PROCEDURE SkipWhite ; | |
119 | ||
120 | ||
121 | (* | |
122 | SkipUntilEoln - skips until a lf is seen. It consumes the lf. | |
123 | *) | |
124 | ||
125 | PROCEDURE SkipUntilEoln ; | |
126 | ||
127 | ||
128 | (* | |
129 | AdvanceToken - advances to the next token. | |
130 | *) | |
131 | ||
132 | PROCEDURE AdvanceToken ; | |
133 | ||
134 | ||
135 | (* | |
136 | IsReserved - returns TRUE if the name is a reserved word. | |
137 | *) | |
138 | ||
139 | PROCEDURE IsReserved (name: Name) : BOOLEAN ; | |
140 | ||
141 | ||
142 | (* | |
143 | PushBackToken - pushes a token back onto input. | |
144 | *) | |
145 | ||
146 | PROCEDURE PushBackToken (t: Name) ; | |
147 | ||
148 | ||
149 | (* | |
150 | SetDebugging - sets the debugging flag. | |
151 | *) | |
152 | ||
153 | PROCEDURE SetDebugging (flag: BOOLEAN) ; | |
154 | ||
155 | ||
156 | END bnflex. |