# Catch without a tag argument **URL:** \ **Category:** Development\ **Created:** [August 22, 2007, 5:34pm UTC](https://www.ruby-forum.com/t/catch-without-a-tag-argument/112732 "2007-08-22T17:34:43Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\ **Post date:** [August 22, 2007, 5:34pm UTC](https://www.ruby-forum.com/t/catch-without-a-tag-argument/112732/1 "2007-08-22T17:34:43Z")
matzruby e$B$K$"$k!"0z?t$J$7$Ge(B catch e$B$,8F$Y$k5!G=$Oe(B 1.9 e$B$K$OF~e(B e$B$i$J$$$N$G$7$g$&$+!#e(B % ./ruby -ve ‘p catch {|t| throw t, 1 }’ ruby 1.9.0 (2007-04-20 patchlevel 0) [i686-linux] - matz 1 % ./ruby -ve ‘p catch {|t| throw t, 1 }’ ruby 1.9.0 (2007-08-22 patchlevel 0) [i686-linux] -e:1:in `catch': wrong number of arguments(0 for 1) (ArgumentError) from -e:1:in`’ ---
**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\ **Post date:** [August 23, 2007, 2:36am UTC](https://www.ruby-forum.com/t/catch-without-a-tag-argument/112732/2 "2007-08-23T02:36:34Z")
e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B In message “Re: [ruby-dev:31615] Re: catch without a tag argument” on Thu, 23 Aug 2007 08:03:19 +0900, Nobuyoshi N. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes: |At Thu, 23 Aug 2007 00:34:12 +0900, |Tanaka A. wrote in [ruby-dev:31609]: |\> matzruby e$B$K$"$k!"0z?t$J$7$Ge(B catch e$B$,8F$Y$k5!G=$Oe(B 1.9 e$B$K$OF~e(B |\> e$B$i$J$$$N$G$7$g$&$+!#e(B | |e$B$$$m$$$m$HJQ$o$C$F$k$h$&$G$=$N$^$^$G$OF0$-$^$;$s$G$7$?!#e(B e$BF~$l$J$$M}M3$O$J$$$N$G$9$,!“$=$N$^$^J|CV$7$F$^$7$?!#$J$+$@$5e(B e$B$s!”%3%\_%C%H$7$F$/$@$5$$!#e(B ---
**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\ **Post date:** [August 23, 2007, 1:04am UTC](https://www.ruby-forum.com/t/catch-without-a-tag-argument/112732/3 "2007-08-23T01:04:28Z")
e$B$J$+$@$G$9!#e(B At Thu, 23 Aug 2007 00:34:12 +0900, Tanaka A. wrote in [ruby-dev:31609]: > matzruby e$B$K$"$k!"0z?t$J$7$Ge(B catch e$B$,8F$Y$k5!G=$Oe(B 1.9 e$B$K$OF~e(B > e$B$i$J$$$N$G$7$g$&$+!#e(B e$B$$$m$$$m$HJQ$o$C$F$k$h$&$G$=$N$^$^$G$OF0$-$^$;$s$G$7$?!#e(B # Index: eval\_jump.ci — eval\_jump.ci (revision 13128) +++ eval\_jump.ci (working copy) @@ -6,5 +6,6 @@ #include “eval\_intern.h” -NORETURN(static VALUE rb\_f\_throw \_((int, VALUE \*))); +NORETURN(static VALUE rb\_f\_throw(int, VALUE \*)); +int rb\_vm\_catch\_p(VALUE dst, VALUE tag); /\* @@ -24,25 +25,8 @@ rb\_f\_throw(int argc, VALUE \*argv) { VALUE tag, value; - rb\_thread\_t \*th = GET\_THREAD(); - struct rb\_vm\_tag \*tt = th-\>tag; - tag = ID2SYM(rb\_to\_id(tag)); - - while (tt) { - if (tt-\>tag == tag) { - ``` tt->retval = value; ``` - ``` break; ``` - } - tt = tt-\>prev; - } - if (!tt) { - rb\_name\_error(SYM2ID(tag), “uncaught throw `%s’”, - ``` rb_id2name(SYM2ID(tag))); ``` - } - rb\_trap\_restore\_mask(); - th-\>errinfo = tag; - JUMP\_TAG(TAG\_THROW); - rb\_throw\_obj(tag, value); #ifndef **GNUC** return Qnil; /\* not reached \*/ @@ -53,14 +37,11 @@ void rb\_throw(const char \*tag, VALUE val) { - VALUE argv[2]; - - argv[0] = ID2SYM(rb\_intern(tag)); - argv[1] = val; - rb\_f\_throw(2, argv); - rb\_throw\_obj(ID2SYM(rb\_intern(tag)), val); } /\* - call-seq: - - ``` catch(symbol) {| | block } > obj ``` - - ``` catch(symbol) { block } => obj ``` - - ``` catch() {|tag| block } => obj ``` - - +catch+ executes its block. If a +throw+ is @@ -92,41 +73,22 @@ rb\_throw(const char \*tag, VALUE val) static VALUE -rb\_f\_catch(VALUE dmy, VALUE tag) +rb\_f\_catch(int argc, VALUE \*argv) { - int state; - VALUE val = Qnil; /\* OK \*/ - rb\_thread\_t \*th = GET\_THREAD(); - - tag = ID2SYM(rb\_to\_id(tag)); - PUSH\_TAG(); - VALUE tag; - th-\>tag-\>tag = tag; - - if ((state = EXEC\_TAG()) == 0) { - val = rb\_yield\_0(1, &tag); - } - else if (state == TAG\_THROW && th-\>errinfo == tag) { - val = th-\>tag-\>retval; - th-\>errinfo = Qnil; - state = 0; - rb\_scan\_args(argc, argv, “01”, &tag); - if (argc == 0) { - tag = Qundef; } - POP\_TAG(); - if (state) - JUMP\_TAG(state); - - return val; -} - -static VALUE -catch\_i(VALUE tag) -{ - return rb\_funcall(Qnil, rb\_intern(“catch”), 1, tag); - return rb\_catch\_obj(tag, rb\_yield, Qnil); } VALUE -rb\_catch(const char \*tag, VALUE (\*func)(), VALUE data) +rb\_catch(const char \*tag, VALUE (\*func)(ANYARGS), VALUE data) { - return rb\_iterate((VALUE (\*)\_((VALUE)))catch\_i, ID2SYM(rb\_intern(tag)), - ``` func, data); ``` - if (!tag) { - return rb\_catch\_obj(Qundef, func, data); - } - return rb\_catch\_obj(ID2SYM(rb\_intern(tag)), func, data); } @@ -277,5 +239,5 @@ void Init\_jump(void) { - rb\_define\_global\_function(“catch”, rb\_f\_catch, 1); - rb\_define\_global\_function(“catch”, rb\_f\_catch, -1); rb\_define\_global\_function(“throw”, rb\_f\_throw, -1); rb\_define\_global\_function(“at\_exit”, rb\_f\_at\_exit, 0); Index: vm.c =================================================================== — vm.c (revision 13128) +++ vm.c (working copy) @@ -982,4 +995,76 @@ rb\_iter\_break() } +static inline int +catching\_p(VALUE dst, VALUE tag) +{ - if (dst == tag) return Qtrue; - if (SPECIAL\_CONST\_P(dst)) return Qfalse; - if (BUILTIN\_TYPE(dst) != T\_NODE) return Qfalse; - if (GET\_THROWOBJ\_STATE(dst) != TAG\_THROW) return Qfalse; - if (GET\_THROWOBJ\_VAL(dst) != tag) return Qfalse; - return Qtrue; +} - +void +rb\_throw\_obj(VALUE tag, VALUE value) +{ - rb\_thread\_t \*th = GET\_THREAD(); - struct rb\_vm\_tag \*tt = th-\>tag; - - while (tt) { - if (catching\_p(tt-\>tag, tag)) { - ``` tag = tt->tag; ``` - ``` tt->retval = value; ``` - ``` break; ``` - } - tt = tt-\>prev; - } - if (!tt) { - VALUE argv[2]; - argv[0] = rb\_sprintf(“uncaught throw `%s’”, RSTRING\_PTR(rb\_obj\_as\_string(tag))); - argv[1] = tag; - rb\_exc\_raise(rb\_class\_new\_instance(2, argv, rb\_eNameError)); - } - rb\_trap\_restore\_mask(); - th-\>errinfo = tag; - TH\_JUMP\_TAG(th, TAG\_THROW); +#ifndef **GNUC** - return Qnil; /\* not reached \*/ +#endif +} - +VALUE +rb\_catch\_obj(VALUE tag, VALUE (\*func)(ANYARGS), VALUE data) +{ - int state; - VALUE val = Qnil; /\* OK \*/ - VALUE dest = tag; - rb\_thread\_t \*th = GET\_THREAD(); - - if (tag == Qundef) { - tag = rb\_obj\_alloc(rb\_cObject); - dest = (VALUE)NEW\_THROW\_OBJECT(tag, GC\_GUARDED\_PTR\_REF(\*th-\>cfp-\>dfp), - ``` TAG_THROW); ``` - } - - TH\_PUSH\_TAG(th); - - th-\>tag-\>tag = dest; - - if ((state = EXEC\_TAG()) == 0) { - val = (\*func)(tag, data); - } - else if (state == TAG\_THROW && th-\>errinfo == dest) { - val = th-\>tag-\>retval; - th-\>errinfo = Qnil; - state = 0; - } - TH\_POP\_TAG(); - if (state) - JUMP\_TAG(state); - - return val; +} - /\* optimization: redefine management \*/ # Index: include/ruby/ruby.h — include/ruby/ruby.h (revision 13128) +++ include/ruby/ruby.h (working copy) @@ -723,5 +723,7 @@ VALUE rb\_rescue2(VALUE(_)(ANYARGS),VALUE VALUE rb\_ensure(VALUE(_)(ANYARGS),VALUE,VALUE(_)(ANYARGS),VALUE); VALUE rb\_catch(const char_,VALUE(_)(ANYARGS),VALUE); +VALUE rb\_catch\_obj(VALUE,VALUE(_)(ANYARGS),VALUE); NORETURN(void rb\_throw(const char\*,VALUE)); +NORETURN(void rb\_throw\_obj(VALUE,VALUE)); VALUE rb\_require(const char\*);