feat: Add a pure JSON backend to Configy

This way we can parse things that are not YAML 1.1 compliant.

Author: Geod24

build-files.txt

@@ -19,6 +19,7 @@ source/dub/generators/targetdescription.d
 source/dub/generators/visuald.d
 source/dub/init.d
 source/dub/internal/configy/attributes.d
+source/dub/internal/configy/backend/json.d
 source/dub/internal/configy/backend/node.d
 source/dub/internal/configy/backend/yaml.d
 source/dub/internal/configy/easy.d

source/dub/internal/configy/backend/json.d

@@ -0,0 +1,106 @@
+/*******************************************************************************
+
+    A backend using `dub.internal.vibecompat.data.json` as parser.
+
+    This is a more JSON-compliant parser than the YAML one (which is used for
+    parsing `dub.json` files) however it doesn't provide location informations
+    that are as good as the YAML parser, hence it is only used for internal
+    files that may have 'special' UTF-8 characters.
+
+    See_Also:
+      https://github.com/dlang-community/D-YAML/issues/342
+
+*******************************************************************************/
+
+module dub.internal.configy.backend.json;
+
+import dub.internal.configy.backend.node;
+import dub.internal.configy.utils;
+import dub.internal.vibecompat.data.json;
+
+import std.algorithm : among;
+import std.exception;
+import std.format;
+
+/*******************************************************************************
+
+    A wrapper around a JSON node
+
+    This node is all types at once, however users should use one of the `asX`
+    method to get some useful value out of it.
+
+*******************************************************************************/
+
+public class JSONNode : Node, Mapping, Sequence, Scalar {
+    /// Underlying data
+    private Json n;
+    ///
+    private string file;
+
+    public this (Json node, string file) @safe {
+        this.n = node;
+        this.file = file;
+    }
+
+    public override Location location () const scope @safe nothrow {
+        // No column information
+        version (JsonLineNumbers)
+            return Location(this.file, this.n.line);
+        else
+            return Location(this.file, 0);
+    }
+
+    public override Type type () const scope @safe nothrow {
+        final switch (this.n.type()) {
+            // Treat `null` and `undefined` as empty mapping
+            case Json.Type.null_:
+            case Json.Type.undefined:
+            case Json.Type.object:
+                return Node.Type.Mapping;
+            case Json.Type.array:
+                return Node.Type.Sequence;
+            case Json.Type.bool_:
+            case Json.Type.int_:
+            case Json.Type.bigInt:
+            case Json.Type.float_:
+            case Json.Type.string:
+                return Node.Type.Scalar;
+        }
+    }
+
+    public override inout(Mapping) asMapping () inout scope return @safe {
+        return this.type() == Node.Type.Mapping ? this : null;
+    }
+    public override inout(Sequence) asSequence () inout scope return @safe {
+        return this.type() == Node.Type.Sequence ? this : null;
+    }
+    public override inout(Scalar) asScalar () inout scope return @safe {
+        // undefined and null can be used as scalar if one so desire
+        return this.n.type().among(Json.Type.object, Json.Type.array) ? null : this;
+    }
+
+    public override string str () const scope return @safe {
+        return this.n.to!string;
+    }
+    public override size_t length () const scope @safe {
+        return this.n.length();
+    }
+    public override int opApply (scope MapIterator dg) scope {
+        foreach (ref string idx, ref Json val; this.n) {
+            scope nIdx = new JSONNode(Json(idx), this.file);
+            version (JsonLineNumbers) nIdx.n.line = val.line;
+            scope Node nVal = new JSONNode(val, this.file);
+            if (auto res = dg(nIdx, nVal))
+                return res;
+        }
+        return 0;
+    }
+    public override int opApply (scope SeqIterator dg) scope {
+        foreach (size_t idx, ref Json val; this.n) {
+            scope nVal = new JSONNode(val, this.file);
+            if (auto res = dg(idx, nVal))
+                return res;
+        }
+        return 0;
+    }
+}

source/dub/internal/configy/easy.d

@@ -205,3 +205,18 @@ public ConfigT parseConfigString (ConfigT)
     auto root = parseString(data, args.config_path);
     return parseConfig!ConfigT(root, strict);
 }
+
+/// ditto
+public ConfigT parseConfigStringJSON (ConfigT)
+    (string data, string path, StrictMode strict = StrictMode.Error)
+{
+    import std.exception;
+    import dub.internal.configy.backend.json;
+    import dub.internal.vibecompat.data.json;
+
+    assert(path.length, "No path provided to parseConfigStringJSON");
+    auto root = new JSONNode(parseJsonString(data, path), path).asMapping();
+    enforce(root !is null, "Parsing '" ~ path ~ "' didn't yield an object");
+    return parseConfig!ConfigT(root, strict);
+
+}