cproc

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commit 88aa3b6891678669548f01a0f87c36a993694320
parent 652fde3ea5a89d44696991db14c18a851914c3ab
Author: Michael Forney <mforney@mforney.org>
Date:   Wed, 17 Apr 2019 13:54:48 -0700

Improve token descriptions in errors

Diffstat:
Mcc.h | 2+-
Mpp.c | 9++++++---
Mtoken.c | 30+++++++++++++++++++++++++++++-
3 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/cc.h b/cc.h @@ -376,8 +376,8 @@ struct init { extern struct token tok; void tokprint(const struct token *); +void tokdesc(char *, size_t, enum tokenkind, const char *); _Noreturn void error(const struct location *, const char *, ...); -struct token; /* scan */ diff --git a/pp.c b/pp.c @@ -124,10 +124,13 @@ peek(int kind) char * expect(int kind, const char *msg) { - char *lit; + char *lit, want[64], got[64]; - if (tok.kind != kind) - error(&tok.loc, "expected %d %s, saw %d", kind, msg, tok.kind); + if (tok.kind != kind) { + tokdesc(want, sizeof(want), kind, NULL); + tokdesc(got, sizeof(got), tok.kind, tok.lit); + error(&tok.loc, "expected %s %s, saw %s", want, msg, got); + } lit = tok.lit; next(); diff --git a/token.c b/token.c @@ -1,4 +1,6 @@ +#include <assert.h> #include <stdarg.h> +#include <stdbool.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> @@ -7,7 +9,7 @@ struct token tok; -static char *tokstr[] = { +static const char *tokstr[] = { /* keyword */ [TAUTO] = "auto", [TBREAK] = "break", @@ -130,6 +132,32 @@ tokprint(const struct token *t) fputs(str, stdout); } +void +tokdesc(char *buf, size_t len, enum tokenkind kind, const char *lit) +{ + const char *class; + bool quote; + + switch (kind) { + case TIDENT: class = "identifier"; quote = true; break; + case TNUMBER: class = "number"; quote = true; break; + case TCHARCONST: class = "character"; quote = false; break; + case TSTRINGLIT: class = "string"; quote = false; break; + case TNEWLINE: class = "newline"; quote = true; break; + default: + class = NULL; + lit = kind < LEN(tokstr) ? tokstr[kind] : NULL; + } + if (class && lit) + snprintf(buf, len, quote ? "%s '%s'" : "%s %s", class, lit); + else if (class) + snprintf(buf, len, "%s", class); + else if (lit) + snprintf(buf, len, "'%s'", lit); + else + snprintf(buf, len, "<unknown>"); +} + _Noreturn void error(const struct location *loc, const char *fmt, ...) { va_list ap;