Merge pull request #7809 from asterite/feature/yaml-string

YAML: let String handle numbers too

spec/std/yaml/mapping_spec.cr

@@ -103,6 +103,12 @@ private class YAMLWithPresence
   })
 end
 
+private class YAMLWithString
+  YAML.mapping({
+    value: String,
+  })
+end
+
 class YAMLRecursive
   YAML.mapping({
     name:  String,
@@ -530,4 +536,12 @@ describe "YAML mapping" do
   it "calls #finalize" do
     assert_finalizes(:yaml) { YAMLWithFinalize.from_yaml("---\nvalue: 1\n") }
   end
+
+  it "parses string even if it looks like a number" do
+    yaml = YAMLWithString.from_yaml <<-YAML
+      ---
+      value: 12.34
+      YAML
+    yaml.value.should eq("12.34")
+  end
 end

spec/std/yaml/serialization_spec.cr

@@ -55,10 +55,8 @@ describe "YAML serialization" do
       String.from_yaml("hello").should eq("hello")
     end
 
-    it "raises on reserved string" do
-      expect_raises(YAML::ParseException) do
-        String.from_yaml(%(1.2))
-      end
+    it "can parse string that looks like a number" do
+      String.from_yaml(%(1.2)).should eq ("1.2")
     end
 
     it "does Float32#from_yaml" do

src/yaml/from_yaml.cr

@@ -53,7 +53,17 @@ end
 {% end %}
 
 def String.new(ctx : YAML::ParseContext, node : YAML::Nodes::Node)
-  parse_scalar(ctx, node, self)
+  ctx.read_alias(node, String) do |obj|
+    return obj
+  end
+
+  if node.is_a?(YAML::Nodes::Scalar)
+    value = node.value
+    ctx.record_anchor(node, value)
+    value
+  else
+    node.raise "Expected String, not #{node.class.name}"
+  end
 end
 
 def Float32.new(ctx : YAML::ParseContext, node : YAML::Nodes::Node)