diff options
Diffstat (limited to 'matchviz.c')
| -rw-r--r-- | matchviz.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/matchviz.c b/matchviz.c new file mode 100644 index 0000000..ebf0ad9 --- /dev/null +++ b/matchviz.c @@ -0,0 +1,171 @@ +// +// debugviz.c - Debug visualization of pattern matches. +// + +#include <stdio.h> +#include <string.h> + +#include "matchviz.h" +#include "types.h" +#include "utils.h" + +typedef struct match_node_s { + match_t *m; + struct match_node_s *next; +} match_node_t; + +__attribute__((nonnull, pure)) +static int height_of_match(match_t *m); +__attribute__((nonnull)) +static void _visualize_matches(match_node_t *firstmatch, int depth, const char *text, size_t textlen); + +// +// Return the height of a match object (i.e. the number of descendents of the +// structure). +// +static int height_of_match(match_t *m) +{ + int height = 0; + for (match_t *c = m->child; c; c = c->nextsibling) { + int childheight = height_of_match(c); + if (childheight > height) height = childheight; + } + return 1 + height; +} + +// +// Print a visual explanation for the as-yet-unprinted matches provided. +// +static void _visualize_matches(match_node_t *firstmatch, int depth, const char *text, size_t textlen) +{ + const char *V = "│"; // Vertical bar + const char *H = "─"; // Horizontal bar + const char *color = (depth % 2 == 0) ? "34" : "33"; + + match_t *viz = firstmatch->m; + // This is a heuristic: print matches first if they have more submatches. + // In general, this helps reduce the height of the final output by allowing + // for more rows that show the same rule matching in multiple places. + // TODO: there may be a better heuristic that optimizes for this factor + // while also printing earlier matches first when it doesn't affect overall + // output height. + for (match_node_t *p = firstmatch; p; p = p->next) + if (height_of_match(p->m) > height_of_match(viz)) + viz = p->m; + const char *viz_type = viz->pat->start; + size_t viz_typelen = (size_t)(viz->pat->end - viz->pat->start); + + // Backrefs use added dim quote marks to indicate that the pattern is a + // literal string being matched. (Backrefs have start/end inside the text + // input, instead of something the user typed in) + if (viz_type >= text && viz_type <= &text[textlen]) + printf("\033[%luG\033[0;2m\"\033[%s;1m", 2*textlen+3, color); + else + printf("\033[%luG\033[%s;1m", 2*textlen+3, color); + + for (size_t i = 0; i < viz_typelen; i++) { + switch (viz_type[i]) { + case '\n': printf("↵"); break; + case '\t': printf("⇥"); break; + default: printf("%c", viz_type[i]); break; + } + } + + if (viz_type >= text && viz_type <= &text[textlen]) + printf("\033[0;2m\""); + + printf("\033[0m"); + + match_node_t *children = NULL; + match_node_t **nextchild = &children; + +#define RIGHT_TYPE(m) (m->m->pat->end == m->m->pat->start + viz_typelen && strncmp(m->m->pat->start, viz_type, viz_typelen) == 0) + // Print nonzero-width first: + for (match_node_t *m = firstmatch; m; m = m->next) { + if (RIGHT_TYPE(m)) { + for (match_t *c = m->m->child; c; c = c->nextsibling) { + *nextchild = new(match_node_t); + (*nextchild)->m = c; + nextchild = &((*nextchild)->next); + } + if (m->m->end == m->m->start) continue; + printf("\033[%ldG\033[0;2m%s\033[0;7;%sm", 1+2*(m->m->start - text), V, color); + for (const char *c = m->m->start; c < m->m->end; ++c) { + // TODO: newline + if (c > m->m->start) printf(" "); + // TODO: utf8 + //while ((*c & 0xC0) != 0x80) printf("%c", *(c++)); + if (*c == '\n') + printf("↵"); + else if (*c == '\t') + printf("⇥"); + else + printf("%c", *c); + } + printf("\033[0;2m%s\033[0m", V); + } else { + *nextchild = new(match_node_t); + (*nextchild)->m = m->m; + nextchild = &((*nextchild)->next); + printf("\033[%ldG\033[0;2m%s", 1+2*(m->m->start - text), V); + for (ssize_t i = (ssize_t)(2*(m->m->end - m->m->start)-1); i > 0; i--) + printf(" "); + if (m->m->end > m->m->start) + printf("\033[0;2m%s", V); + printf("\033[0m"); + } + } + + // Print stars for zero-width: + for (match_node_t *m = firstmatch; m; m = m->next) { + if (m->m->end > m->m->start) continue; + if (RIGHT_TYPE(m)) { + printf("\033[%ldG\033[7;%sm▒\033[0m", 1+2*(m->m->start - text), color); + } else { + printf("\033[%ldG\033[0;2m%s\033[0m", 1+2*(m->m->start - text), V); + } + } + + printf("\n"); + + for (match_node_t *m = firstmatch; m; m = m->next) { + if (m->m->end == m->m->start) { + if (!RIGHT_TYPE(m)) + printf("\033[%ldG\033[0;2m%s", 1 + 2*(m->m->start - text), V); + } else { + const char *l = "└"; + const char *r = "┘"; + for (match_node_t *c = children; c; c = c->next) { + if (c->m->start == m->m->start || c->m->end == m->m->start) l = V; + if (c->m->start == m->m->end || c->m->end == m->m->end) r = V; + } + printf("\033[%ldG\033[0;2m%s", 1 + 2*(m->m->start - text), l); + const char *h = RIGHT_TYPE(m) ? H : " "; + for (ssize_t n = (ssize_t)(2*(m->m->end - m->m->start) - 1); n > 0; n--) + printf("%s", h); + printf("%s\033[0m", r); + } + } +#undef RIGHT_TYPE + + printf("\n"); + + if (children) + _visualize_matches(children, depth+1, text, textlen); + + for (match_node_t *c = children, *next = NULL; c; c = next) { + next = c->next; + xfree(&c); + } +} + +// +// Print a visualization of a match object. +// +void visualize_match(match_t *m) +{ + printf("\033[?7l"); // Disable line wrapping + match_node_t first = {.m = m}; + _visualize_matches(&first, 0, m->start, (size_t)(m->end - m->start)); + printf("\033[?7h"); // Re-enable line wrapping +} |