53e569c06
Denys Vlasenko
2018-12-25
Subject
bc: fix interactive read()
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miscutils/bc.c+26 -25
| @@ -6753,6 +6753,7 @@ static BC_STATUS zbc_vm_process(const char *text) | |
| s = zbc_parse_text_init(&G.prs, text); // does the first zbc_lex_next() | |
| if (s) RETURN_STATUS(s); | |
| + | IF_BC(check_eof:) |
| while (G.prs.l.lex != XC_LEX_EOF) { | |
| BcInstPtr *ip; | |
| BcFunc *f; | |
| @@ -6760,34 +6761,34 @@ 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) { | |
| #if ENABLE_BC | |
| + | if (G.prs.l.lex == BC_LEX_SCOLON |
| + | || G.prs.l.lex == XC_LEX_NLINE |
| + | ) { |
| + | s = zbc_lex_next(&G.prs.l); |
| + | if (s) goto err; |
| + | goto check_eof; |
| + | } |
| + | |
| 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; |
| + | // Check that next token is a correct stmt delimiter - |
| + | // disallows "print 1 print 2" and such. |
| + | if (G.prs.l.lex != BC_LEX_SCOLON |
| + | && G.prs.l.lex != XC_LEX_NLINE |
| + | && G.prs.l.lex != XC_LEX_EOF |
| + | ) { |
| + | const char *err_at; |
| + | //TODO: commonalize 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; |
| } | |
| + | // The above logic is fragile. Check these examples: |
| + | // - interative read() still works |
| #endif | |
| } else { | |
| #if ENABLE_DC | |
| @@ -6807,7 +6808,7 @@ static BC_STATUS zbc_vm_process(const char *text) | |
| 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) { | |