Implement .def/.defined expressions

This can be combined with .if/.elsif statements just like any other
expression.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/xixanta/src/node.rs b/lib/xixanta/src/node.rs
index ae79f1e..f1eb558 100644
--- a/lib/xixanta/src/node.rs
+++ b/lib/xixanta/src/node.rs
@@ -147,6 +147,7 @@ pub enum ControlType {
     Elsif,
     Else,
     EndIf,
+    Defined,
 }
 
 impl fmt::Display for ControlType {
@@ -174,6 +175,7 @@ impl fmt::Display for ControlType {
             ControlType::Elsif => write!(f, ".elsif"),
             ControlType::Else => write!(f, ".else"),
             ControlType::EndIf => write!(f, ".endif"),
+            ControlType::Defined => write!(f, ".defined"),
         }
     }
 }