Add support for partial classes

Fixes https://gitlab.gnome.org/GNOME/vala/issues/370

4 files changed, 58 insertions, 2 deletions

diff --git a/vala/valaclass.vala b/vala/valaclass.vala
index ee4ed624f..a6f5ae633 100644
--- a/vala/valaclass.vala
+++ b/vala/valaclass.vala
@@ -37,6 +37,8 @@ public class Vala.Class : ObjectTypeSymbol {
 	 */
 	public bool is_abstract { get; set; }
 
+	public bool is_partial { get; set; }
+
 	/**
 	 * Specifies whether this class is sealed. Sealed classes may not be
 	 * sub-classed.
diff --git a/vala/valaparser.vala b/vala/valaparser.vala
index f71f6e89c..a2b99f9ed 100644
--- a/vala/valaparser.vala
+++ b/vala/valaparser.vala
@@ -61,7 +61,8 @@ public class Vala.Parser : CodeVisitor {
 		STATIC,
 		VIRTUAL,
 		ASYNC,
-		SEALED
+		SEALED,
+		PARTIAL
 	}
 
 	public Parser () {
@@ -253,6 +254,7 @@ public class Vala.Parser : CodeVisitor {
 		case TokenType.OVERRIDE:
 		case TokenType.OWNED:
 		case TokenType.PARAMS:
+		case TokenType.PARTIAL:
 		case TokenType.PRIVATE:
 		case TokenType.PROTECTED:
 		case TokenType.PUBLIC:
@@ -2733,6 +2735,7 @@ public class Vala.Parser : CodeVisitor {
 			case TokenType.NAMESPACE:
 			case TokenType.NEW:
 			case TokenType.OVERRIDE:
+			case TokenType.PARTIAL:
 			case TokenType.PRIVATE:
 			case TokenType.PROTECTED:
 			case TokenType.PUBLIC:
@@ -2842,9 +2845,42 @@ public class Vala.Parser : CodeVisitor {
 		if (ModifierFlags.SEALED in flags) {
 			cl.is_sealed = true;
 		}
+		if (ModifierFlags.PARTIAL in flags) {
+			if (!context.experimental) {
+				Report.warning (cl.source_reference, "`partial' classes are experimental");
+			}
+			cl.is_partial = true;
+		}
 		if (ModifierFlags.EXTERN in flags) {
 			cl.is_extern = true;
 		}
+
+		var old_cl = parent.scope.lookup (cl.name) as Class;
+		if (old_cl != null && old_cl.is_partial) {
+			if (cl.is_partial != old_cl.is_partial) {
+				Report.error (cl.source_reference, "conflicting partial and not partial declarations of `%s'".printf (cl.name));
+				cl.error = true;
+			}
+			if (cl.access != old_cl.access) {
+				Report.error (cl.source_reference, "partial declarations of `%s' have conflicting accessiblity modifiers".printf (cl.name));
+				cl.error = true;
+			}
+			if (cl.is_abstract != old_cl.is_abstract) {
+				Report.error (cl.source_reference, "partial declarations of `%s' have conflicting abstract modifiers".printf (cl.name));
+				cl.error = true;
+			}
+			if (cl.is_sealed != old_cl.is_sealed) {
+				Report.error (cl.source_reference, "partial declarations of `%s' have conflicting sealed modifiers".printf (cl.name));
+				cl.error = true;
+			}
+			if (cl.error) {
+				Report.notice (old_cl.source_reference, "previous declaration of `%s' was here", old_cl.name);
+				return;
+			}
+
+			cl = old_cl;
+		}
+
 		set_attributes (cl, attrs);
 		foreach (TypeParameter type_param in type_param_list) {
 			cl.add_type_parameter (type_param);
@@ -2855,6 +2891,10 @@ public class Vala.Parser : CodeVisitor {
 
 		parse_declarations (cl);
 
+		if (old_cl != null && old_cl.is_partial) {
+			return;
+		}
+
 		// ensure there is always a default construction method
 		if (scanner.source_file.file_type == SourceFileType.SOURCE
 		    && cl.default_construction_method == null) {
@@ -3530,6 +3570,10 @@ public class Vala.Parser : CodeVisitor {
 				next ();
 				flags |= ModifierFlags.EXTERN;
 				break;
+			case TokenType.PARTIAL:
+				next ();
+				flags |= ModifierFlags.PARTIAL;
+				break;
 			case TokenType.SEALED:
 				next ();
 				flags |= ModifierFlags.SEALED;
@@ -3872,6 +3916,7 @@ public class Vala.Parser : CodeVisitor {
 		case TokenType.NAMESPACE:
 		case TokenType.NEW:
 		case TokenType.OVERRIDE:
+		case TokenType.PARTIAL:
 		case TokenType.PRIVATE:
 		case TokenType.PROTECTED:
 		case TokenType.PUBLIC:
diff --git a/vala/valascanner.vala b/vala/valascanner.vala
index 36f274e6f..daeb97feb 100644
--- a/vala/valascanner.vala
+++ b/vala/valascanner.vala
@@ -533,7 +533,14 @@ public class Vala.Scanner {
 				}
 				break;
 			case 'p':
-				if (matches (begin, "private")) return TokenType.PRIVATE;
+				switch (begin[1]) {
+				case 'r':
+					if (matches (begin, "private")) return TokenType.PRIVATE;
+					break;
+				case 'a':
+					if (matches (begin, "partial")) return TokenType.PARTIAL;
+					break;
+				}
 				break;
 			case 'u':
 				if (matches (begin, "unowned")) return TokenType.UNOWNED;
diff --git a/vala/valatokentype.vala b/vala/valatokentype.vala
index 9cc6d1c74..2c64ec1b0 100644
--- a/vala/valatokentype.vala
+++ b/vala/valatokentype.vala
@@ -115,6 +115,7 @@ public enum Vala.TokenType {
 	OVERRIDE,
 	OWNED,
 	PARAMS,
+	PARTIAL,
 	PERCENT,
 	PLUS,
 	PRIVATE,
@@ -249,6 +250,7 @@ public enum Vala.TokenType {
 		case OVERRIDE: return "`override'";
 		case OWNED: return "`owned'";
 		case PARAMS: return "`params'";
+		case PARTIAL: return "`partial'";
 		case PERCENT: return "`%'";
 		case PLUS: return "`+'";
 		case PRIVATE: return "`private'";