diff options
Diffstat (limited to 'eval_jump.c')
| -rw-r--r-- | eval_jump.c | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/eval_jump.c b/eval_jump.c new file mode 100644 index 0000000000..948ac635be --- /dev/null +++ b/eval_jump.c @@ -0,0 +1,305 @@ +/* -*-c-*- */ +/* + * from eval.c + */ + +#include "eval_intern.h" + +NORETURN(static VALUE rb_f_throw _((int, VALUE *))); + +/* + * call-seq: + * throw(symbol [, obj]) + * + * Transfers control to the end of the active +catch+ block + * waiting for _symbol_. Raises +NameError+ if there + * is no +catch+ block for the symbol. The optional second + * parameter supplies a return value for the +catch+ block, + * which otherwise defaults to +nil+. For examples, see + * <code>Kernel::catch</code>. + */ + +static VALUE +rb_f_throw(int argc, VALUE *argv) +{ + VALUE tag, value; + rb_thread_t *th = GET_THREAD(); + struct rb_vm_tag *tt = th->tag; + + rb_scan_args(argc, argv, "11", &tag, &value); + while (tt) { + if (tt->tag == tag) { + tt->retval = value; + break; + } + tt = tt->prev; + } + if (!tt) { + VALUE desc = rb_inspect(tag); + rb_raise(rb_eArgError, "uncaught throw %s", RSTRING_PTR(desc)); + } + rb_trap_restore_mask(); + th->errinfo = NEW_THROW_OBJECT(tag, 0, TAG_THROW); + + JUMP_TAG(TAG_THROW); +#ifndef __GNUC__ + return Qnil; /* not reached */ +#endif +} + +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); +} + +void +rb_throw_obj(VALUE tag, VALUE val) +{ + VALUE argv[2]; + + argv[0] = tag; + argv[1] = val; + rb_f_throw(2, argv); +} + +/* + * call-seq: + * catch(symbol) {| | block } > obj + * + * +catch+ executes its block. If a +throw+ is + * executed, Ruby searches up its stack for a +catch+ block + * with a tag corresponding to the +throw+'s + * _symbol_. If found, that block is terminated, and + * +catch+ returns the value given to +throw+. If + * +throw+ is not called, the block terminates normally, and + * the value of +catch+ is the value of the last expression + * evaluated. +catch+ expressions may be nested, and the + * +throw+ call need not be in lexical scope. + * + * def routine(n) + * puts n + * throw :done if n <= 0 + * routine(n-1) + * end + * + * + * catch(:done) { routine(3) } + * + * <em>produces:</em> + * + * 3 + * 2 + * 1 + * 0 + */ + +static VALUE +rb_f_catch(int argc, VALUE *argv) +{ + VALUE tag; + int state; + VALUE val = Qnil; /* OK */ + rb_thread_t *th = GET_THREAD(); + + rb_scan_args(argc, argv, "01", &tag); + if (argc == 0) { + tag = rb_obj_alloc(rb_cObject); + } + PUSH_TAG(); + + th->tag->tag = tag; + + if ((state = EXEC_TAG()) == 0) { + val = rb_yield_0(1, &tag); + } + else if (state == TAG_THROW && RNODE(th->errinfo)->u1.value == tag) { + val = th->tag->retval; + th->errinfo = Qnil; + state = 0; + } + POP_TAG(); + if (state) + JUMP_TAG(state); + + return val; +} + +static VALUE +catch_null_i(VALUE dmy) +{ + return rb_funcall(Qnil, rb_intern("catch"), 0, 0); +} + +static VALUE +catch_i(VALUE tag) +{ + return rb_funcall(Qnil, rb_intern("catch"), 1, tag); +} + +VALUE +rb_catch(const char *tag, VALUE (*func)(), VALUE data) +{ + if (!tag) { + return rb_iterate(catch_null_i, 0, func, data); + } + return rb_iterate(catch_i, ID2SYM(rb_intern(tag)), func, data); +} + +VALUE +rb_catch_obj(VALUE tag, VALUE (*func)(), VALUE data) +{ + return rb_iterate((VALUE (*)_((VALUE)))catch_i, tag, func, data); +} + + +/* exit */ + +void +rb_call_end_proc(VALUE data) +{ + rb_proc_call(data, rb_ary_new()); +} + +/* + * call-seq: + * at_exit { block } -> proc + * + * Converts _block_ to a +Proc+ object (and therefore + * binds it at the point of call) and registers it for execution when + * the program exits. If multiple handlers are registered, they are + * executed in reverse order of registration. + * + * def do_at_exit(str1) + * at_exit { print str1 } + * end + * at_exit { puts "cruel world" } + * do_at_exit("goodbye ") + * exit + * + * <em>produces:</em> + * + * goodbye cruel world + */ + +static VALUE +rb_f_at_exit(void) +{ + VALUE proc; + + if (!rb_block_given_p()) { + rb_raise(rb_eArgError, "called without a block"); + } + proc = rb_block_proc(); + rb_set_end_proc(rb_call_end_proc, proc); + return proc; +} + +struct end_proc_data { + void (*func) (); + VALUE data; + int safe; + struct end_proc_data *next; +}; + +static struct end_proc_data *end_procs, *ephemeral_end_procs, *tmp_end_procs; + +void +rb_set_end_proc(void (*func)(VALUE), VALUE data) +{ + struct end_proc_data *link = ALLOC(struct end_proc_data); + struct end_proc_data **list; + rb_thread_t *th = GET_THREAD(); + + if (th->top_wrapper) { + list = &ephemeral_end_procs; + } + else { + list = &end_procs; + } + link->next = *list; + link->func = func; + link->data = data; + link->safe = rb_safe_level(); + *list = link; +} + +void +rb_mark_end_proc(void) +{ + struct end_proc_data *link; + + link = end_procs; + while (link) { + rb_gc_mark(link->data); + link = link->next; + } + link = ephemeral_end_procs; + while (link) { + rb_gc_mark(link->data); + link = link->next; + } + link = tmp_end_procs; + while (link) { + rb_gc_mark(link->data); + link = link->next; + } +} + +void +rb_exec_end_proc(void) +{ + struct end_proc_data *link, *tmp; + int status; + volatile int safe = rb_safe_level(); + + while (ephemeral_end_procs) { + tmp_end_procs = link = ephemeral_end_procs; + ephemeral_end_procs = 0; + while (link) { + PUSH_TAG(); + if ((status = EXEC_TAG()) == 0) { + rb_set_safe_level_force(link->safe); + (*link->func) (link->data); + } + POP_TAG(); + if (status) { + error_handle(status); + } + tmp = link; + tmp_end_procs = link = link->next; + free(tmp); + } + } + while (end_procs) { + tmp_end_procs = link = end_procs; + end_procs = 0; + while (link) { + PUSH_TAG(); + if ((status = EXEC_TAG()) == 0) { + rb_set_safe_level_force(link->safe); + (*link->func) (link->data); + } + POP_TAG(); + if (status) { + error_handle(status); + } + tmp = link; + tmp_end_procs = link = link->next; + free(tmp); + } + } + rb_set_safe_level_force(safe); +} + +void +Init_jump(void) +{ + 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); +} |