From ad48387aa0536cb40a3b2849363d90ef52f46aac Mon Sep 17 00:00:00 2001
From: JT <jonathan.d.turner@gmail.com>
Date: Sat, 24 Jul 2021 18:44:38 +1200
Subject: [PATCH] WIP

---
 src/eval.rs   | 31 +++++++++++++++++++++++++++++++
 src/main.rs   |  2 +-
 src/parser.rs |  3 +++
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/src/eval.rs b/src/eval.rs
index 30bf276fc6..29d62824ab 100644
--- a/src/eval.rs
+++ b/src/eval.rs
@@ -103,6 +103,37 @@ fn eval_call(state: &State, stack: &mut Stack, call: &Call) -> Result<Value, She
 
             stack.add_var(var_id, rhs);
             Ok(Value::Unknown)
+        } else if decl.signature.name == "if" {
+            let cond = &call.positional[0];
+            let then_block = call.positional[1]
+                .as_block()
+                .expect("internal error: expected block");
+            let else_case = call.positional.get(2);
+
+            let result = eval_expression(state, stack, cond)?;
+            match result {
+                Value::Bool { val, .. } => {
+                    if val {
+                        let block = state.parser_state.get_block(then_block);
+                        eval_block(state, stack, block)
+                    } else if let Some(else_case) = else_case {
+                        println!("{:?}", else_case);
+                        if let Some(else_expr) = else_case.as_keyword() {
+                            if let Some(block_id) = else_expr.as_block() {
+                                let block = state.parser_state.get_block(block_id);
+                                eval_block(state, stack, block)
+                            } else {
+                                eval_expression(state, stack, else_expr)
+                            }
+                        } else {
+                            eval_expression(state, stack, else_case)
+                        }
+                    } else {
+                        Ok(Value::Unknown)
+                    }
+                }
+                _ => Err(ShellError::Mismatch("bool".into(), Span::unknown())),
+            }
         } else {
             Ok(Value::Unknown)
         }
diff --git a/src/main.rs b/src/main.rs
index ef90257728..04a4a07128 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -19,7 +19,7 @@ fn main() -> std::io::Result<()> {
             .required("then_block", SyntaxShape::Block, "then block")
             .optional(
                 "else",
-                SyntaxShape::Keyword(b"else".to_vec(), Box::new(SyntaxShape::Block)),
+                SyntaxShape::Keyword(b"else".to_vec(), Box::new(SyntaxShape::Expression)),
                 "optional else followed by else block",
             );
         working_set.add_decl(sig.into());
diff --git a/src/parser.rs b/src/parser.rs
index 10bb480b67..d0bf685134 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -936,6 +936,9 @@ impl<'a> ParserWorkingSet<'a> {
                     None,
                 )
             } else {
+                let name = self.get_span_contents(span).to_vec();
+                // this seems okay to set it to unknown here, but we should double-check
+                let id = self.add_variable(name, Type::Unknown);
                 (
                     Expression::garbage(span),
                     Some(ParseError::VariableNotFound(span)),