diff options
Diffstat (limited to 'enum.c')
-rw-r--r-- | enum.c | 125 |
1 files changed, 125 insertions, 0 deletions
@@ -3083,6 +3083,130 @@ enum_slice_before(int argc, VALUE *argv, VALUE enumerable) return enumerator; } + +struct sliceafter_arg { + VALUE pat; + VALUE pred; + VALUE prev_elts; + VALUE yielder; +}; + +static VALUE +sliceafter_ii(RB_BLOCK_CALL_FUNC_ARGLIST(i, _memo)) +{ +#define UPDATE_MEMO ((memo = MEMO_FOR(struct sliceafter_arg, _memo)), 1) + struct sliceafter_arg *memo; + int split_p; + UPDATE_MEMO; + + ENUM_WANT_SVALUE(); + + if (NIL_P(memo->prev_elts)) { + memo->prev_elts = rb_ary_new3(1, i); + } + else { + rb_ary_push(memo->prev_elts, i); + } + + if (NIL_P(memo->pred)) { + split_p = RTEST(rb_funcall(memo->pat, id_eqq, 1, i)); + UPDATE_MEMO; + } + else { + split_p = RTEST(rb_funcall(memo->pred, id_call, 1, i)); + UPDATE_MEMO; + } + + if (split_p) { + rb_funcall(memo->yielder, id_lshift, 1, memo->prev_elts); + UPDATE_MEMO; + memo->prev_elts = Qnil; + } + + return Qnil; +#undef UPDATE_MEMO +} + +static VALUE +sliceafter_i(RB_BLOCK_CALL_FUNC_ARGLIST(yielder, enumerator)) +{ + VALUE enumerable; + VALUE arg; + struct sliceafter_arg *memo = NEW_MEMO_FOR(struct sliceafter_arg, arg); + + enumerable = rb_ivar_get(enumerator, rb_intern("sliceafter_enum")); + memo->pat = rb_ivar_get(enumerator, rb_intern("sliceafter_pat")); + memo->pred = rb_attr_get(enumerator, rb_intern("sliceafter_pred")); + memo->prev_elts = Qnil; + memo->yielder = yielder; + + rb_block_call(enumerable, id_each, 0, 0, sliceafter_ii, arg); + memo = MEMO_FOR(struct sliceafter_arg, arg); + if (!NIL_P(memo->prev_elts)) + rb_funcall(memo->yielder, id_lshift, 1, memo->prev_elts); + return Qnil; +} + +/* + * call-seq: + * enum.slice_after(pattern) -> an_enumerator + * enum.slice_after { |elt| bool } -> an_enumerator + * + * Creates an enumerator for each chunked elements. + * The ends of chunks are defined by _pattern_ and the block. + * + * If <code>_pattern_ === _elt_</code> returns <code>true</code> or the block + * returns <code>true</code> for the element, the element is end of a + * chunk. + * + * The <code>===</code> and _block_ is called from the first element to the last + * element of _enum_. + * + * The result enumerator yields the chunked elements as an array. + * So +each+ method can be called as follows: + * + * enum.slice_after(pattern).each { |ary| ... } + * enum.slice_after { |elt| bool }.each { |ary| ... } + * + * Other methods of the Enumerator class and Enumerable module, + * such as +map+, etc., are also usable. + * + * For example, continuation lines (lines end with backslash) can be + * concatenated as follows: + * + * lines = ["foo\n", "bar\\\n", "baz\n", "\n", "qux\n"] + * e = lines.slice_after(/(?<!\\)\n\z/) + * p e.to_a + * #=> [["foo\n"], ["bar\\\n", "baz\n"], ["\n"], ["qux\n"]] + * p e.map {|ll| ll[0...-1].map {|l| l.sub(/\\\n\z/, "") }.join + ll.last } + * #=>["foo\n", "barbaz\n", "\n", "qux\n"] + * + */ + +static VALUE +enum_slice_after(int argc, VALUE *argv, VALUE enumerable) +{ + VALUE enumerator; + VALUE pat = Qnil, pred = Qnil; + + if (rb_block_given_p()) { + if (0 < argc) + rb_raise(rb_eArgError, "both pattan and block are given"); + pred = rb_block_proc(); + } + else { + rb_scan_args(argc, argv, "1", &pat); + } + + enumerator = rb_obj_alloc(rb_cEnumerator); + rb_ivar_set(enumerator, rb_intern("sliceafter_enum"), enumerable); + rb_ivar_set(enumerator, rb_intern("sliceafter_pat"), pat); + rb_ivar_set(enumerator, rb_intern("sliceafter_pred"), pred); + + rb_block_call(enumerator, idInitialize, 0, 0, sliceafter_i, enumerator); + return enumerator; +} + /* * The <code>Enumerable</code> mixin provides collection classes with * several traversal and searching methods, and with the ability to @@ -3151,6 +3275,7 @@ Init_Enumerable(void) rb_define_method(rb_mEnumerable, "cycle", enum_cycle, -1); rb_define_method(rb_mEnumerable, "chunk", enum_chunk, -1); rb_define_method(rb_mEnumerable, "slice_before", enum_slice_before, -1); + rb_define_method(rb_mEnumerable, "slice_after", enum_slice_after, -1); id_next = rb_intern("next"); id_call = rb_intern("call"); |