From 583eddc3bf4c84f1ff7a88d4e3575835264208fa Mon Sep 17 00:00:00 2001 From: Robin Haberkorn Date: Sun, 2 Feb 2025 17:58:20 +0300 Subject: redefining labels is a warning now * Allowing label redefinitions might have been useful when used as comments, since you will want to be able to define arbitrary comments. However as flow control constructs, this introduced a certain ambiguity since gotos might jump to different locations, depending on the progression of the parser. * On the other hand, making label redefinition an error might disqualify labels as comments when writing or porting classic TECO code. Therefore, it has been made a warning as a compromise. * Added test case --- src/goto-commands.c | 18 +++++--- src/goto.c | 119 ++++++++++++++++++++++++++++------------------------ src/goto.h | 6 +-- 3 files changed, 80 insertions(+), 63 deletions(-) (limited to 'src') diff --git a/src/goto-commands.c b/src/goto-commands.c index ad802e0..b87fc32 100644 --- a/src/goto-commands.c +++ b/src/goto-commands.c @@ -30,6 +30,7 @@ #include "lexer.h" #include "core-commands.h" #include "undo.h" +#include "interface.h" #include "goto.h" #include "goto-commands.h" @@ -62,15 +63,20 @@ teco_state_label_input(teco_machine_main_t *ctx, gunichar chr, GError **error) } if (chr == '!') { - /* - * NOTE: If the label already existed, its PC will be restored - * on rubout. - * Otherwise, the label will be removed (PC == -1). - */ gssize existing_pc = teco_goto_table_set(&ctx->goto_table, ctx->goto_label.data, ctx->goto_label.len, ctx->macro_pc); + if (existing_pc == ctx->macro_pc) + /* encountered the same label again */ + return &teco_state_start; + if (existing_pc >= 0) { + g_autofree gchar *label_printable = teco_string_echo(ctx->goto_label.data, + ctx->goto_label.len); + teco_interface_msg(TECO_MSG_WARNING, "Ignoring goto label \"%s\" redefinition", + label_printable); + return &teco_state_start; + } if (ctx->parent.must_undo) - teco_goto_table_undo_set(&ctx->goto_table, ctx->goto_label.data, ctx->goto_label.len, existing_pc); + teco_goto_table_undo_remove(&ctx->goto_table, ctx->goto_label.data, ctx->goto_label.len); if (teco_goto_skip_label.len > 0 && !teco_string_cmp(&ctx->goto_label, teco_goto_skip_label.data, teco_goto_skip_label.len)) { diff --git a/src/goto.c b/src/goto.c index 1076532..855c9f9 100644 --- a/src/goto.c +++ b/src/goto.c @@ -78,53 +78,26 @@ teco_goto_table_dump(teco_goto_table_t *ctx) } #endif -/** @memberof teco_goto_table_t */ -gssize +/** + * Remove label from goto table. + * + * @param ctx Goto table + * @param name Label name + * @param len Length of label name + * @return TRUE if the label existed and was removed + * + * @memberof teco_goto_table_t + */ +gboolean teco_goto_table_remove(teco_goto_table_t *ctx, const gchar *name, gsize len) { - gssize existing_pc = -1; - teco_goto_label_t *label = (teco_goto_label_t *)teco_rb3str_find(&ctx->tree, TRUE, name, len); - if (label) { - existing_pc = label->pc; - rb3_unlink_and_rebalance(&label->head.head); - teco_goto_label_free(label); - } + if (!label) + return FALSE; - return existing_pc; -} - -/** @memberof teco_goto_table_t */ -gssize -teco_goto_table_find(teco_goto_table_t *ctx, const gchar *name, gsize len) -{ - teco_goto_label_t *label = (teco_goto_label_t *)teco_rb3str_find(&ctx->tree, TRUE, name, len); - return label ? label->pc : -1; -} - -/** @memberof teco_goto_table_t */ -gssize -teco_goto_table_set(teco_goto_table_t *ctx, const gchar *name, gsize len, gssize pc) -{ - if (pc < 0) - return teco_goto_table_remove(ctx, name, len); - - gssize existing_pc = -1; - - teco_goto_label_t *label = (teco_goto_label_t *)teco_rb3str_find(&ctx->tree, TRUE, name, len); - if (label) { - existing_pc = label->pc; - label->pc = pc; - } else { - label = teco_goto_label_new(name, len, pc); - teco_rb3str_insert(&ctx->tree, TRUE, &label->head); - } - -#ifdef DEBUG - teco_goto_table_dump(ctx); -#endif - - return existing_pc; + rb3_unlink_and_rebalance(&label->head.head); + teco_goto_label_free(label); + return TRUE; } /* @@ -135,41 +108,79 @@ teco_goto_table_set(teco_goto_table_t *ctx, const gchar *name, gsize len, gssize */ typedef struct { teco_goto_table_t *table; - gssize pc; gsize len; gchar name[]; -} teco_goto_table_undo_set_t; +} teco_goto_table_undo_remove_t; static void -teco_goto_table_undo_set_action(teco_goto_table_undo_set_t *ctx, gboolean run) +teco_goto_table_undo_remove_action(teco_goto_table_undo_remove_t *ctx, gboolean run) { - if (run) { - teco_goto_table_set(ctx->table, ctx->name, ctx->len, ctx->pc); + if (!run) + return; + + G_GNUC_UNUSED gboolean removed = teco_goto_table_remove(ctx->table, ctx->name, ctx->len); + g_assert(removed == TRUE); #ifdef DEBUG - teco_goto_table_dump(ctx->table); + teco_goto_table_dump(ctx->table); #endif - } } /** @memberof teco_goto_table_t */ void -teco_goto_table_undo_set(teco_goto_table_t *ctx, const gchar *name, gsize len, gssize pc) +teco_goto_table_undo_remove(teco_goto_table_t *ctx, const gchar *name, gsize len) { if (!ctx->must_undo) return; - teco_goto_table_undo_set_t *token; - token = teco_undo_push_size((teco_undo_action_t)teco_goto_table_undo_set_action, + teco_goto_table_undo_remove_t *token; + token = teco_undo_push_size((teco_undo_action_t)teco_goto_table_undo_remove_action, sizeof(*token) + len); if (token) { token->table = ctx; - token->pc = pc; token->len = len; if (name) memcpy(token->name, name, len); } } +/** @memberof teco_goto_table_t */ +gssize +teco_goto_table_find(teco_goto_table_t *ctx, const gchar *name, gsize len) +{ + teco_goto_label_t *label = (teco_goto_label_t *)teco_rb3str_find(&ctx->tree, TRUE, name, len); + return label ? label->pc : -1; +} + +/** + * Insert label into goto table. + * + * @param ctx Goto table + * @param name Label name + * @param len Length of label name + * @param pc Program counter of the new label + * @return The program counter of any label of the same name + * or -1. The label is inserted only if there is no label in the + * table already. + * + * @memberof teco_goto_table_t + */ +gssize +teco_goto_table_set(teco_goto_table_t *ctx, const gchar *name, gsize len, gsize pc) +{ + gssize existing_pc = teco_goto_table_find(ctx, name, len); + if (existing_pc >= 0) + return existing_pc; + + teco_goto_label_t *label = teco_goto_label_new(name, len, pc); + teco_rb3str_insert(&ctx->tree, TRUE, &label->head); + +#ifdef DEBUG + teco_goto_table_dump(ctx); +#endif + + return -1; +} + /** @memberof teco_goto_table_t */ void teco_goto_table_clear(teco_goto_table_t *ctx) diff --git a/src/goto.h b/src/goto.h index 49007fb..eda823f 100644 --- a/src/goto.h +++ b/src/goto.h @@ -40,12 +40,12 @@ teco_goto_table_init(teco_goto_table_t *ctx, gboolean must_undo) ctx->must_undo = must_undo; } -gssize teco_goto_table_remove(teco_goto_table_t *ctx, const gchar *name, gsize len); +gboolean teco_goto_table_remove(teco_goto_table_t *ctx, const gchar *name, gsize len); +void teco_goto_table_undo_remove(teco_goto_table_t *ctx, const gchar *name, gsize len); gssize teco_goto_table_find(teco_goto_table_t *ctx, const gchar *name, gsize len); -gssize teco_goto_table_set(teco_goto_table_t *ctx, const gchar *name, gsize len, gssize pc); -void teco_goto_table_undo_set(teco_goto_table_t *ctx, const gchar *name, gsize len, gssize pc); +gssize teco_goto_table_set(teco_goto_table_t *ctx, const gchar *name, gsize len, gsize pc); /** @memberof teco_goto_table_t */ static inline gboolean -- cgit v1.2.3