Adds if/else value node.

2 files changed, 154 insertions, 3 deletions

diff --git a/src/core/src/tonkadur/fate/v1/lang/IfElseValue.java b/src/core/src/tonkadur/fate/v1/lang/IfElseValue.java
new file mode 100644
index 0000000..960af57
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/IfElseValue.java
@@ -0,0 +1,141 @@
+package tonkadur.fate.v1.lang;
+
+import java.util.Set;
+import java.util.Map;
+import java.util.HashMap;
+import java.util.Collections;
+
+import tonkadur.error.ErrorManager;
+
+import tonkadur.parser.Origin;
+
+import tonkadur.fate.v1.lang.meta.ValueNode;
+
+import tonkadur.fate.v1.error.ConflictingTypeException;
+import tonkadur.fate.v1.error.IncomparableTypeException;
+import tonkadur.fate.v1.error.InvalidTypeException;
+
+public class IfElseValue extends ValueNode
+{
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final ValueNode condition;
+   protected final ValueNode if_true;
+   protected final ValueNode if_false;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected IfElseValue
+   (
+      final Origin origin,
+      final Type return_type,
+      final ValueNode condition,
+      final ValueNode if_true,
+      final ValueNode if_false
+   )
+   {
+      super(origin, return_type);
+
+      this.condition = condition;
+      this.if_true = if_true;
+      this.if_false = if_false;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   public static IfElseValue build
+   (
+      final Origin origin,
+      final ValueNode condition,
+      final ValueNode if_true,
+      final ValueNode if_false
+   )
+   throws
+      InvalidTypeException,
+      ConflictingTypeException,
+      IncomparableTypeException
+   {
+      final Type hint;
+      final Type if_true_type;
+      final Type if_false_type;
+
+      if (!condition.get_type().can_be_used_as(Type.BOOLEAN))
+      {
+         ErrorManager.handle
+         (
+            new InvalidTypeException
+            (
+               origin,
+               condition.get_type(),
+               Collections.singleton(Type.BOOLEAN)
+            )
+         );
+      }
+
+      if_true_type = if_true.get_type();
+      if_false_type = if_false.get_type();
+
+      if (if_true_type.equals(if_false_type))
+      {
+         return
+            new IfElseValue(origin, if_true_type, condition, if_true, if_false);
+      }
+
+      ErrorManager.handle
+      (
+         new ConflictingTypeException(origin, if_false_type, if_true_type)
+      );
+
+      hint =
+         (Type) if_false_type.generate_comparable_to(if_true_type);
+
+      if (hint.equals(Type.ANY))
+      {
+         ErrorManager.handle
+         (
+            new IncomparableTypeException(origin, if_false_type, if_true_type)
+         );
+      }
+
+      return new IfElseValue(origin, hint, condition, if_true, if_false);
+   }
+
+   /**** Accessors ************************************************************/
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append(origin.toString());
+      sb.append("(IfElseValue");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("Condition:");
+      sb.append(System.lineSeparator());
+      sb.append(condition.toString());
+
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+      sb.append("If true:");
+      sb.append(System.lineSeparator());
+      sb.append(if_true.toString());
+
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+      sb.append("If false:");
+      sb.append(System.lineSeparator());
+      sb.append(if_false.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/parser/FateParser.g4 b/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
index 2585948..27ff773 100644
--- a/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
+++ b/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
@@ -654,10 +654,20 @@ returns [ValueNode result]
 non_text_value
 returns [ValueNode result]
 :
-   IF_ELSE_KW value WS+ value WS+ value R_PAREN
+   IF_ELSE_KW cond=value WS+ if_true=value WS+ if_false=value R_PAREN
    {
-      /* TODO */
-      $result = null;
+      $result =
+         IfElseValue.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($IF_ELSE_KW.getLine()),
+               ($IF_ELSE_KW.getCharPositionInLine())
+            ),
+            ($cond.result),
+            ($if_true.result),
+            ($if_false.result)
+         );
    }
 
    | COND_KW value_cond_list R_PAREN