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9a3f3b7b ML |
1 | /* Copyright (c) 1982 Regents of the University of California */ |
2 | ||
550fe947 | 3 | static char sccsid[] = "@(#)keywords.c 1.2 %G%"; |
9a3f3b7b ML |
4 | |
5 | /* | |
6 | * Keyword management. | |
7 | */ | |
8 | ||
9 | #include "defs.h" | |
10 | #include "keywords.h" | |
11 | #include "scanner.h" | |
12 | #include "names.h" | |
13 | #include "symbols.h" | |
14 | #include "tree.h" | |
15 | #include "y.tab.h" | |
16 | ||
17 | #ifndef public | |
18 | #include "scanner.h" | |
19 | #endif | |
20 | ||
21 | private String reserved[] ={ | |
22 | "alias", "and", "assign", "at", "call", "catch", "cont", | |
23 | "delete", "div", "dump", "edit", "file", "func", | |
24 | "gripe", "help", "if", "ignore", "in", | |
25 | "list", "mod", "next", "nexti", "nil", "not", "or", | |
26 | "print", "psym", "quit", "run", | |
27 | "sh", "skip", "source", "status", "step", "stepi", | |
28 | "stop", "stopi", "trace", "tracei", | |
29 | "use", "whatis", "when", "where", "whereis", "which", | |
30 | "INT", "REAL", "NAME", "STRING", | |
31 | "LFORMER", "RFORMER", "#^", "->" | |
32 | }; | |
33 | ||
34 | /* | |
35 | * The keyword table is a traditional hash table with collisions | |
36 | * resolved by chaining. | |
37 | */ | |
38 | ||
39 | #define HASHTABLESIZE 503 | |
40 | ||
41 | typedef struct Keyword { | |
42 | Name name; | |
43 | Token toknum : 16; | |
44 | Boolean isalias : 16; | |
45 | struct Keyword *chain; | |
46 | } *Keyword; | |
47 | ||
48 | typedef unsigned int Hashvalue; | |
49 | ||
50 | private Keyword hashtab[HASHTABLESIZE]; | |
51 | ||
52 | #define hash(n) ((((unsigned) n) >> 2) mod HASHTABLESIZE) | |
53 | ||
54 | /* | |
55 | * Enter all the reserved words into the keyword table. | |
56 | */ | |
57 | ||
58 | public enterkeywords() | |
59 | { | |
60 | register Integer i; | |
61 | ||
62 | for (i = ALIAS; i <= WHICH; i++) { | |
63 | keyword(reserved[ord(i) - ord(ALIAS)], i, false); | |
64 | } | |
65 | keyword("set", ASSIGN, false); | |
66 | } | |
67 | ||
68 | /* | |
69 | * Deallocate the keyword table. | |
70 | */ | |
71 | ||
72 | public keywords_free() | |
73 | { | |
74 | register Integer i; | |
75 | register Keyword k, nextk; | |
76 | ||
77 | for (i = 0; i < HASHTABLESIZE; i++) { | |
78 | k = hashtab[i]; | |
79 | while (k != nil) { | |
80 | nextk = k->chain; | |
81 | dispose(k); | |
82 | k = nextk; | |
83 | } | |
84 | hashtab[i] = nil; | |
85 | } | |
86 | } | |
87 | ||
88 | /* | |
89 | * Enter a keyword into the name table. It is assumed to not be there already. | |
90 | * The string is assumed to be statically allocated. | |
91 | */ | |
92 | ||
93 | private keyword(s, t, isalias) | |
94 | String s; | |
95 | Token t; | |
96 | Boolean isalias; | |
97 | { | |
98 | register Hashvalue h; | |
99 | register Keyword k; | |
100 | Name n; | |
101 | ||
102 | n = identname(s, true); | |
103 | h = hash(n); | |
104 | k = new(Keyword); | |
105 | k->name = n; | |
106 | k->toknum = t; | |
107 | k->isalias = isalias; | |
108 | k->chain = hashtab[h]; | |
109 | hashtab[h] = k; | |
110 | } | |
111 | ||
112 | /* | |
113 | * Return the string associated with a token corresponding to a keyword. | |
114 | */ | |
115 | ||
116 | public String keywdstring(t) | |
117 | Token t; | |
118 | { | |
119 | return reserved[ord(t) - ord(ALIAS)]; | |
120 | } | |
121 | ||
122 | /* | |
123 | * Find a keyword in the keyword table. | |
124 | * We assume that tokens cannot legitimately be nil (0). | |
125 | */ | |
126 | ||
127 | public Token findkeyword(n) | |
128 | Name n; | |
129 | { | |
130 | register Hashvalue h; | |
131 | register Keyword k; | |
132 | Token t; | |
133 | ||
134 | h = hash(n); | |
135 | k = hashtab[h]; | |
136 | while (k != nil and k->name != n) { | |
137 | k = k->chain; | |
138 | } | |
139 | if (k == nil) { | |
140 | t = nil; | |
141 | } else { | |
142 | t = k->toknum; | |
143 | } | |
144 | return t; | |
145 | } | |
146 | ||
147 | /* | |
148 | * Create an alias. | |
149 | */ | |
150 | ||
151 | public enter_alias(newcmd, oldcmd) | |
152 | Name newcmd; | |
153 | Name oldcmd; | |
154 | { | |
155 | Token t; | |
156 | ||
157 | t = findkeyword(oldcmd); | |
158 | if (t == nil) { | |
159 | error("\"%s\" is not a command", ident(oldcmd)); | |
160 | } else { | |
161 | keyword(ident(newcmd), t, true); | |
162 | } | |
163 | } | |
164 | ||
165 | /* | |
166 | * Print out an alias. | |
167 | */ | |
168 | ||
169 | public print_alias(cmd) | |
170 | Name cmd; | |
171 | { | |
172 | register Keyword k; | |
173 | register Integer i; | |
174 | Token t; | |
175 | ||
176 | if (cmd == nil) { | |
177 | for (i = 0; i < HASHTABLESIZE; i++) { | |
178 | for (k = hashtab[i]; k != nil; k = k->chain) { | |
179 | if (k->isalias) { | |
180 | if (isredirected()) { | |
181 | printf("alias "); | |
182 | } | |
183 | printf("%s\t%s\n", ident(k->name), keywdstring(k->toknum)); | |
184 | } | |
185 | } | |
186 | } | |
187 | } else { | |
188 | t = findkeyword(cmd); | |
189 | if (t == nil) { | |
190 | printf("\n"); | |
191 | } else { | |
192 | printf("%s\n", keywdstring(t)); | |
193 | } | |
194 | } | |
195 | } |