1 /* PSPP - computes sample statistics.
2 Copyright (C) 1997-9, 2000 Free Software Foundation, Inc.
3 Written by Ben Pfaff <blp@gnu.org>.
5 This program is free software; you can redistribute it and/or
6 modify it under the terms of the GNU General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 This program is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
32 #include "debug-print.h"
39 /* Description of DO IF transformations:
41 DO IF has two transformations. One is a conditional jump around
42 a false condition. The second is an unconditional jump around
43 the rest of the code after a true condition. Both of these types
44 have their destinations backpatched in by the next clause (ELSE IF,
47 The characters `^V<>' are meant to represent arrows.
52 V *. Transformations executed when the condition on DO IF is true.
54 V 2. GOTO>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>V
59 V *. Transformations executed when condition on 1st ELSE IF is true. V
61 V 2. GOTO>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>V
66 V *. Transformations executed when condition on 2nd ELSE IF is true. V
68 V 2. GOTO>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>V
70 >>*. Transformations executed when no condition is true. (ELSE) V
72 *. Transformations after DO IF structure.<<<<<<<<<<<<<<<<<<<<<<<<<<<<
77 static struct do_if_trns *parse_do_if (void);
78 static void add_ELSE_IF (struct do_if_trns *);
79 static int goto_trns_proc (struct trns_header *, struct ccase *);
80 static int do_if_trns_proc (struct trns_header *, struct ccase *);
81 static void do_if_trns_free (struct trns_header *);
89 /* Parse the transformation. */
94 /* Finish up the transformation, add to control stack, add to
95 transformation list. */
97 t->ctl.type = CST_DO_IF;
98 t->ctl.down = ctl_stack;
99 t->ctl.trns = (struct trns_header *) t;
103 add_transformation ((struct trns_header *) t);
112 /* Transformation created. */
113 struct do_if_trns *t;
115 /* Check that we're in a pleasing situation. */
116 if (!ctl_stack || ctl_stack->type != CST_DO_IF)
118 msg (SE, _("There is no DO IF to match with this ELSE IF."));
121 if (((struct do_if_trns *) ctl_stack->trns)->has_else)
123 msg (SE, _("The ELSE command must follow all ELSE IF commands "
124 "in a DO IF structure."));
128 /* Parse the transformation. */
133 /* Stick in the breakout transformation. */
134 t->brk = xmalloc (sizeof *t->brk);
135 t->brk->h.proc = goto_trns_proc;
136 t->brk->h.free = NULL;
138 /* Add to list of transformations, add to string of ELSE IFs. */
139 add_transformation ((struct trns_header *) t->brk);
140 add_transformation ((struct trns_header *) t);
146 msg (SE, _("End of command expected."));
147 return CMD_TRAILING_GARBAGE;
157 struct do_if_trns *t;
159 lex_match_id ("ELSE");
161 /* Check that we're in a pleasing situation. */
162 if (!ctl_stack || ctl_stack->type != CST_DO_IF)
164 msg (SE, _("There is no DO IF to match with this ELSE."));
168 if (((struct do_if_trns *) ctl_stack->trns)->has_else)
170 msg (SE, _("There may be at most one ELSE clause in each DO IF "
171 "structure. It must be the last clause."));
175 /* Note that the ELSE transformation is *not* added to the list of
176 transformations. That's because it doesn't need to do anything.
177 Its goto transformation *is* added, because that's necessary.
178 The main DO IF do_if_trns is the destructor for this ELSE
180 t = xmalloc (sizeof *t);
182 t->brk = xmalloc (sizeof *t->brk);
183 t->brk->h.proc = goto_trns_proc;
184 t->brk->h.free = NULL;
186 add_transformation ((struct trns_header *) t->brk);
187 t->h.index = t->brk->h.index + 1;
189 /* Add to string of ELSE IFs. */
192 return lex_end_of_command ();
200 struct do_if_trns *iter;
204 /* Check that we're in a pleasing situation. */
205 if (!ctl_stack || ctl_stack->type != CST_DO_IF)
207 msg (SE, _("There is no DO IF to match with this END IF."));
211 /* Chain down the list, backpatching destinations for gotos. */
212 iter = (struct do_if_trns *) ctl_stack->trns;
216 iter->brk->dest = n_trns;
217 iter->missing_jump = n_trns;
223 iter->false_jump = n_trns;
225 /* Pop control stack. */
226 ctl_stack = ctl_stack->down;
228 return lex_end_of_command ();
231 /* Adds an ELSE IF or ELSE to the chain of them that hangs off the
234 add_ELSE_IF (struct do_if_trns * t)
237 struct do_if_trns *iter;
239 iter = (struct do_if_trns *) ctl_stack->trns;
242 assert (iter != NULL);
245 iter->false_jump = t->h.index;
248 /* Parses a DO IF or ELSE IF command and returns a pointer to a mostly
249 filled in transformation. */
250 static struct do_if_trns *
253 struct do_if_trns *t;
254 struct expression *e;
258 e = expr_parse (PXP_BOOLEAN);
264 lex_error (_("expecting end of command"));
268 t = xmalloc (sizeof *t);
269 t->h.proc = do_if_trns_proc;
270 t->h.free = do_if_trns_free;
277 /* Executes a goto transformation. */
279 goto_trns_proc (struct trns_header * t, struct ccase * c UNUSED)
281 return ((struct goto_trns *) t)->dest;
285 do_if_trns_proc (struct trns_header * trns, struct ccase * c)
287 struct do_if_trns *t = (struct do_if_trns *) trns;
290 expr_evaluate (t->cond, c, &bool);
293 debug_printf ((_("DO IF %d: true\n"), t->h.index));
296 else if (bool.f == 0.0)
298 debug_printf ((_("DO IF %d: false\n"), t->h.index));
299 return t->false_jump;
303 debug_printf ((_("DO IF %d: missing\n"), t->h.index));
304 return t->missing_jump;
309 do_if_trns_free (struct trns_header * trns)
311 struct do_if_trns *t = (struct do_if_trns *) trns;
314 /* If brk is NULL then this is the main DO IF; therefore we
315 need to chain down to the ELSE and delete it. */
318 struct do_if_trns *iter = t->next;
323 /* This is the ELSE. */