Add 'xo-expression/' from commit '5ac3c03a0c'

git-subtree-dir: xo-expression
git-subtree-mainline: d0f5ccc1ce
git-subtree-split: 5ac3c03a0c

xo-expression/src/expression/IfExpr.cpp

@@ -0,0 +1,45 @@
+/* @file IfExpr.cpp */
+
+#include "IfExpr.hpp"
+#include "xo/indentlog/print/vector.hpp"
+
+namespace xo {
+    namespace ast {
+        rp<IfExpr>
+        IfExpr::make(const rp<Expression> & test,
+                     const rp<Expression> & when_true,
+                     const rp<Expression> & when_false)
+        {
+            /** TODO: verify test returns _boolean_ type **/
+
+            if (when_true->valuetype() != when_false->valuetype()) {
+                throw std::runtime_error
+                    (tostr("IfExpr::make:"
+                           " types {T1,T2} found for branches of if-expr"
+                           " where equal types expected",
+                           xtag("T1", when_true->valuetype()->canonical_name()),
+                           xtag("T2", when_false->valuetype()->canonical_name())));
+            }
+
+            /* arbitrary choice here */
+            auto ifexpr_type = when_true->valuetype();
+
+            return new IfExpr(ifexpr_type,
+                              test,
+                              when_true,
+                              when_false);
+        } /*make*/
+
+        void
+        IfExpr::display(std::ostream & os) const {
+            os << "<IfExpr"
+               << xtag("test", test_)
+               << xtag("when_true", when_true_)
+               << xtag("when_false", when_false_)
+               << ">";
+        } /*display*/
+    } /*namespace ast*/
+} /*namespace xo*/
+
+
+/* end IfExpr.cpp */