Add String#lines

mrbgems/mruby-string-ext/src/string.c

 #include <ctype.h>
 #include <string.h>
 #include "mruby.h"
+#include "mruby/array.h"
+#include "mruby/class.h"
 #include "mruby/string.h"
 
 static mrb_value
@@ -190,6 +192,53 @@ mrb_str_chr(mrb_state *mrb, mrb_value self)
   return mrb_str_substr(mrb, self, 0, 1);
 }
 
+/*
+ *  call-seq:
+ *     string.lines    ->  array of string
+ *
+ *  Returns strings per line;
+ *
+ *     a = "abc\ndef"
+ *     a.lines    #=> ["abc", "def"]
+ */
+static mrb_value
+mrb_str_lines(mrb_state *mrb, mrb_value self)
+{
+  mrb_value result;
+  mrb_value blk;
+  int ai;
+  mrb_int len;
+  mrb_value arg;
+  char *p = RSTRING_PTR(self), *t;
+  char *e = p + RSTRING_LEN(self);
+
+  mrb_get_args(mrb, "&", &blk);
+
+  result = mrb_ary_new(mrb);
+
+  if (!mrb_nil_p(blk)) {
+    while (p < e) {
+      t = p;
+      while (p < e && *p != '\n') p++;
+      if (*p == '\n') p++;
+      len = (mrb_int) (p - t);
+      arg = mrb_str_new(mrb, t, len);
+      mrb_yield_argv(mrb, blk, 1, &arg);
+    }
+    return self;
+  }
+  while (p < e) {
+    ai = mrb_gc_arena_save(mrb);
+    t = p;
+    while (p < e && *p != '\n') p++;
+    if (*p == '\n') p++;
+    len = (mrb_int) (p - t);
+    mrb_ary_push(mrb, result, mrb_str_new(mrb, t, len));
+    mrb_gc_arena_restore(mrb, ai);
+  }
+  return result;
+}
+
 void
 mrb_mruby_string_ext_gem_init(mrb_state* mrb)
 {
@@ -206,6 +255,7 @@ mrb_mruby_string_ext_gem_init(mrb_state* mrb)
   mrb_define_method(mrb, s, "hex",             mrb_str_hex,             MRB_ARGS_NONE());
   mrb_define_method(mrb, s, "oct",             mrb_str_oct,             MRB_ARGS_NONE());
   mrb_define_method(mrb, s, "chr",             mrb_str_chr,             MRB_ARGS_NONE());
+  mrb_define_method(mrb, s, "lines",           mrb_str_lines,           MRB_ARGS_NONE());
 }
 
 void

mrbgems/mruby-string-ext/test/string.rb

@@ -165,3 +165,10 @@ end
 assert('String#chr') do
   assert_equal "a", "abcde".chr
 end
+
+assert('String#lines') do
+  assert_equal ["こん\n", "にちは\n", "世界!"], "こん\nにちは\n世界!".lines
+  assert_equal ["こん\n", "にちは\n", "世界!\n"], "こん\nにちは\n世界!\n".lines
+  assert_equal ["\n", "\n", "\n"], "\n\n\n".lines
+  assert_equal [], "".lines
+end