--- /dev/null
+/* PSPP - a program for statistical analysis.
+ Copyright (C) 1997-9, 2000, 2009-2012 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+#include <stdlib.h>
+
+#include "data/dataset.h"
+#include "data/transformations.h"
+#include "language/command.h"
+#include "language/commands/inpt-pgm.h"
+#include "language/expressions/public.h"
+#include "language/lexer/lexer.h"
+#include "libpspp/compiler.h"
+#include "libpspp/message.h"
+#include "libpspp/str.h"
+
+#include "gl/xalloc.h"
+
+#include "gettext.h"
+#define _(msgid) gettext (msgid)
+
+/* A conditional clause. */
+struct clause
+ {
+ struct msg_location *location;
+ struct expression *condition; /* Test expression; NULL for ELSE clause. */
+ struct trns_chain xforms;
+ };
+
+/* DO IF transformation. */
+struct do_if_trns
+ {
+ struct clause *clauses; /* Clauses. */
+ size_t n_clauses; /* Number of clauses. */
+
+ const struct trns_chain *resume;
+ size_t ofs;
+ };
+
+static const struct trns_class do_if_trns_class;
+
+static void
+start_clause (struct lexer *lexer, struct dataset *ds,
+ bool condition, struct do_if_trns *do_if,
+ size_t *allocated_clauses, bool *ok)
+{
+ if (*ok && do_if->n_clauses > 0
+ && !do_if->clauses[do_if->n_clauses - 1].condition)
+ {
+ if (condition)
+ lex_ofs_error (lexer, 0, 1,
+ _("ELSE IF is not allowed following ELSE "
+ "within DO IF...END IF."));
+ else
+ lex_ofs_error (lexer, 0, 0,
+ _("Only one ELSE is allowed within DO IF...END IF."));
+
+ msg_at (SN, do_if->clauses[do_if->n_clauses - 1].location,
+ _("This is the location of the previous ELSE clause."));
+
+ msg_at (SN, do_if->clauses[0].location,
+ _("This is the location of the DO IF command."));
+
+ *ok = false;
+ }
+
+ if (do_if->n_clauses >= *allocated_clauses)
+ do_if->clauses = x2nrealloc (do_if->clauses, allocated_clauses,
+ sizeof *do_if->clauses);
+ struct clause *clause = &do_if->clauses[do_if->n_clauses++];
+
+ *clause = (struct clause) { .location = NULL };
+ if (condition)
+ {
+ clause->condition = expr_parse_bool (lexer, ds);
+ if (!clause->condition)
+ lex_discard_rest_of_command (lexer);
+ }
+ clause->location = lex_ofs_location (lexer, 0, lex_ofs (lexer));
+
+ lex_end_of_command (lexer);
+ lex_get (lexer);
+
+ proc_push_transformations (ds);
+}
+
+static void
+finish_clause (struct dataset *ds, struct do_if_trns *do_if)
+{
+ struct clause *clause = &do_if->clauses[do_if->n_clauses - 1];
+ proc_pop_transformations (ds, &clause->xforms);
+}
+
+/* Parse DO IF. */
+int
+cmd_do_if (struct lexer *lexer, struct dataset *ds)
+{
+ struct do_if_trns *do_if = xmalloc (sizeof *do_if);
+ *do_if = (struct do_if_trns) { .n_clauses = 0 };
+
+ size_t allocated_clauses = 0;
+ bool ok = true;
+
+ start_clause (lexer, ds, true, do_if, &allocated_clauses, &ok);
+ while (!lex_match_phrase (lexer, "END IF"))
+ {
+ if (lex_token (lexer) == T_STOP)
+ {
+ lex_error_expecting (lexer, "END IF");
+ break;
+ }
+ else if (lex_match_phrase (lexer, "ELSE IF"))
+ {
+ finish_clause (ds, do_if);
+ start_clause (lexer, ds, true, do_if, &allocated_clauses, &ok);
+ }
+ else if (lex_match_id (lexer, "ELSE"))
+ {
+ finish_clause (ds, do_if);
+ start_clause (lexer, ds, false, do_if, &allocated_clauses, &ok);
+ }
+ else
+ cmd_parse_in_state (lexer, ds,
+ (in_input_program ()
+ ? CMD_STATE_NESTED_INPUT_PROGRAM
+ : CMD_STATE_NESTED_DATA));
+ }
+ finish_clause (ds, do_if);
+
+ add_transformation (ds, &do_if_trns_class, do_if);
+
+ return ok ? CMD_SUCCESS : CMD_FAILURE;
+}
+
+int
+cmd_inside_do_if (struct lexer *lexer, struct dataset *ds UNUSED)
+{
+ lex_ofs_error (lexer, 0, lex_ofs (lexer) - 1,
+ _("This command cannot appear outside DO IF...END IF."));
+ return CMD_FAILURE;
+}
+
+static const struct trns_chain *
+do_if_find_clause (const struct do_if_trns *do_if,
+ struct ccase *c, casenumber case_num)
+{
+ for (size_t i = 0; i < do_if->n_clauses; i++)
+ {
+ const struct clause *clause = &do_if->clauses[i];
+ if (!clause->condition)
+ return &clause->xforms;
+
+ double boolean = expr_evaluate_num (clause->condition, c, case_num);
+ if (boolean != 0.0)
+ return boolean == SYSMIS ? NULL : &clause->xforms;
+ }
+ return NULL;
+}
+
+static enum trns_result
+do_if_trns_proc (void *do_if_, struct ccase **c, casenumber case_num)
+{
+ struct do_if_trns *do_if = do_if_;
+
+ const struct trns_chain *chain;
+ size_t start;
+ if (do_if->resume)
+ {
+ chain = do_if->resume;
+ start = do_if->ofs;
+ do_if->resume = NULL;
+ do_if->ofs = 0;
+ }
+ else
+ {
+ chain = do_if_find_clause (do_if, *c, case_num);
+ if (!chain)
+ return TRNS_CONTINUE;
+ start = 0;
+ }
+
+ for (size_t i = start; i < chain->n; i++)
+ {
+ const struct transformation *trns = &chain->xforms[i];
+ enum trns_result r = trns->class->execute (trns->aux, c, case_num);
+ switch (r)
+ {
+ case TRNS_CONTINUE:
+ break;
+
+ case TRNS_BREAK:
+ case TRNS_DROP_CASE:
+ case TRNS_ERROR:
+ case TRNS_END_FILE:
+ return r;
+
+ case TRNS_END_CASE:
+ do_if->resume = chain;
+ do_if->ofs = i;
+ return r;
+ }
+ }
+ return TRNS_CONTINUE;
+}
+
+static bool
+do_if_trns_free (void *do_if_)
+{
+ struct do_if_trns *do_if = do_if_;
+
+ for (size_t i = 0; i < do_if->n_clauses; i++)
+ {
+ struct clause *clause = &do_if->clauses[i];
+
+ msg_location_destroy (clause->location);
+ expr_free (clause->condition);
+
+ trns_chain_uninit (&clause->xforms);
+ }
+ free (do_if->clauses);
+ free (do_if);
+ return true;
+}
+
+static const struct trns_class do_if_trns_class = {
+ .name = "DO IF",
+ .execute = do_if_trns_proc,
+ .destroy = do_if_trns_free,
+};
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