263845446
Denys Vlasenko
2018-12-25
Subject
bc: add code to detect errors like "print 1 print 2"
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miscutils/bc.c+39 -10
| @@ -711,6 +711,7 @@ dc_LEX_to_INST[] = { // starts at XC_LEX_OP_POWER // corresponding XC/DC_L | |
| typedef struct BcLex { | |
| const char *buf; | |
| + | const char *lex_next_at; // last lex_next() was called at this string |
| size_t i; | |
| size_t line; | |
| size_t len; | |
| @@ -2990,9 +2991,11 @@ static BC_STATUS zbc_lex_next(BcLex *l) | |
| } | |
| // here it's guaranteed that l->i is below l->len | |
| } | |
| + | l->lex_next_at = l->buf + l->i; |
| dbg_lex("next string to parse:'%.*s'", | |
| - | (int)(strchrnul(l->buf + l->i, '\n') - (l->buf + l->i)), |
| - | l->buf + l->i); |
| + | (int)(strchrnul(l->lex_next_at, '\n') - l->lex_next_at), |
| + | l->lex_next_at |
| + | ); |
| if (IS_BC) { | |
| IF_BC(s = zbc_lex_token(l)); | |
| } else { | |
| @@ -6756,13 +6759,38 @@ static BC_STATUS zbc_vm_process(const char *text) | |
| dbg_lex("%s:%d G.prs.l.lex:%d, parsing...", __func__, __LINE__, G.prs.l.lex); | |
| if (IS_BC) { | |
| - | // FIXME: "eating" of stmt delimiters is coded inconsistently |
| - | // (sometimes zbc_parse_stmt() eats the delimiter, sometimes don't), |
| - | // which causes bugs such as "print 1 print 2" erroneously accepted, |
| - | // or "print 1 else 2" detecting parse error only after executing |
| - | // "print 1" part. |
| - | IF_BC(s = zbc_parse_stmt_or_funcdef(&G.prs)); |
| + | #if ENABLE_BC |
| + | s = zbc_parse_stmt_or_funcdef(&G.prs); |
| + | if (s) goto err; |
| + | |
| + | // Check that next token is not bogus, and skip over |
| + | // stmt delimiter(s) - newlines and semicolons |
| + | s = 1; // s == 1 on first iteration only |
| + | for (;;) { |
| + | if (G.prs.l.lex == XC_LEX_EOF) |
| + | goto execute; // this goto avoids resetting 's' to zero |
| + | if (G.prs.l.lex != BC_LEX_SCOLON |
| + | && G.prs.l.lex != XC_LEX_NLINE |
| + | ) { |
| + | const char *err_at; |
| + | // Not newline and not semicolon |
| + | if (s == 0) // saw at least one NL/semicolon before it? |
| + | break; // yes, good |
| + | //TODO: commolalize for other parse errors: |
| + | err_at = G.prs.l.lex_next_at ? G.prs.l.lex_next_at : "UNKNOWN"; |
| + | bc_error_fmt("bad statement terminator at '%.*s'", |
| + | (int)(strchrnul(err_at, '\n') - err_at), |
| + | err_at |
| + | ); |
| + | goto err; |
| + | } |
| + | // NL or semicolon: skip it, set s = 0, repeat |
| + | s = zbc_lex_next(&G.prs.l); |
| + | if (s) goto err; |
| + | } |
| + | #endif |
| } else { | |
| + | #if ENABLE_DC |
| // Most of dc parsing assumes all whitespace, | |
| // including '\n', is eaten. | |
| while (G.prs.l.lex == XC_LEX_NLINE) { | |
| @@ -6771,14 +6799,15 @@ static BC_STATUS zbc_vm_process(const char *text) | |
| if (G.prs.l.lex == XC_LEX_EOF) | |
| goto done; | |
| } | |
| - | IF_DC(s = zdc_parse_expr(&G.prs)); |
| + | s = zdc_parse_expr(&G.prs); |
| + | #endif |
| } | |
| if (s || G_interrupt) { | |
| err: | |
| bc_parse_reset(&G.prs); // includes bc_program_reset() | |
| RETURN_STATUS(BC_STATUS_FAILURE); | |
| } | |
| - | |
| + | IF_BC(execute:) |
| dbg_lex("%s:%d executing...", __func__, __LINE__); | |
| s = zbc_program_exec(); | |
| if (s) { | |