bc: fix interactive read()

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/miscutils/bc.c b/miscutils/bc.c
index 8b44d44254f2cd4e453cfbb875305ab822df1049..79f981eaf6b28644aae616ec852dcb19ef4bfc45 100644 (file)
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -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) {