Split up if chains more

Signed-off-by: Marcel Müller <neikos@neikos.email>

src/ast/mod.rs

@@ -228,10 +228,12 @@ pub enum TemplateAstExpr<'input> {
     },
     IfConditional {
         if_block: Box<TemplateAstExpr<'input>>,
+    },
+    ConditionalContent {
         content: Vec<TemplateAstExpr<'input>>,
     },
     ElseConditional {
-        expression: Vec<TemplateAstExpr<'input>>,
+        expression: Option<Box<TemplateAstExpr<'input>>>,
     },
     Invalid(&'input [TemplateToken]),
     EndBlock,
@@ -314,21 +316,45 @@ fn parse_conditional_chain<'input>(
     input: &mut Input<'input>,
 ) -> Result<TemplateAstExpr<'input>, AstError> {
     trace("conditional_chain", |input: &mut Input<'input>| {
-        let if_block = parse_conditional.map(Box::new).parse_next(input)?;
+        let if_block = parse_conditional_if.map(Box::new).parse_next(input)?;
         let mut chain = vec![];
 
-        let (content, end_block): (Vec<_>, _) =
-            repeat_till(0.., parse_ast, parse_end).parse_next(input)?;
+        chain.push(TemplateAstExpr::IfConditional { if_block });
+
+        loop {
+            let (content, end_block): (Vec<_>, _) = repeat_till(
+                0..,
+                parse_ast,
+                trace(
+                    "conditional_chain_else/end",
+                    alt((parse_end, parse_conditional_else)),
+                ),
+            )
+            .parse_next(input)?;
+
+            chain.push(TemplateAstExpr::ConditionalContent { content });
+
+            let is_end = if let TemplateAstExpr::Block { ref expression, .. } = end_block
+                && let TemplateAstExpr::EndBlock = &**expression
+            {
+                true
+            } else {
+                false
+            };
 
-        chain.push(TemplateAstExpr::IfConditional { if_block, content });
             chain.push(end_block);
 
+            if dbg!(is_end) {
+                break;
+            }
+        }
+
         Ok(TemplateAstExpr::ConditionalChain { chain })
     })
     .parse_next(input)
 }
 
-fn parse_conditional<'input>(
+fn parse_conditional_if<'input>(
     input: &mut Input<'input>,
 ) -> Result<TemplateAstExpr<'input>, AstError> {
     trace(
@@ -344,6 +370,27 @@ fn parse_conditional<'input>(
     .parse_next(input)
 }
 
+fn parse_conditional_else<'input>(
+    input: &mut Input<'input>,
+) -> Result<TemplateAstExpr<'input>, AstError> {
+    trace(
+        "conditional_else",
+        parse_block(
+            preceded(
+                surrounded(ws, TokenKind::ConditionalElse),
+                opt(preceded(
+                    TokenKind::ConditionalIf,
+                    cut_err(surrounded(ws, parse_value_expression)).map(Box::new),
+                )),
+            )
+            .map(|else_expr| TemplateAstExpr::ElseConditional {
+                expression: else_expr,
+            }),
+        ),
+    )
+    .parse_next(input)
+}
+
 fn parse_end<'input>(input: &mut Input<'input>) -> Result<TemplateAstExpr<'input>, AstError> {
     trace(
         "end",
@@ -440,6 +487,18 @@ mod tests {
     use crate::ast::parse_end;
     use crate::parser::TokenKind;
 
+    fn panic_pretty<'a>(
+        input: &'_ str,
+        tokens: Result<TemplateAst<'a>, AstFailure>,
+    ) -> TemplateAst<'a> {
+        match tokens {
+            Ok(ast) => ast,
+            Err(failure) => {
+                panic!("{}", failure.to_report(input));
+            }
+        }
+    }
+
     #[test]
     fn check_only_content() {
         let input = "Hello World";
@@ -493,7 +552,7 @@ mod tests {
 
         let parsed = crate::parser::parse(input.into()).unwrap();
 
-        let ast = parse(parsed.tokens()).unwrap();
+        let ast = panic_pretty(input, parse(parsed.tokens()));
 
         insta::assert_debug_snapshot!(ast, @r#"
         TemplateAst {
@@ -510,6 +569,8 @@ mod tests {
                                     [Whitespace]" " (12..13),
                                 ),
                             },
+                        },
+                        ConditionalContent {
                             content: [
                                 StaticContent(
                                     [Content]"Hiii" (13..17),
@@ -530,18 +591,6 @@ mod tests {
         "#);
     }
 
-    fn panic_pretty<'a>(
-        input: &'_ str,
-        tokens: Result<TemplateAst<'a>, AstFailure>,
-    ) -> TemplateAst<'a> {
-        match tokens {
-            Ok(ast) => ast,
-            Err(failure) => {
-                panic!("{}", failure.to_report(input));
-            }
-        }
-    }
-
     #[test]
     fn check_invalid_action() {
         let input = r#"{{ value }}
@@ -624,4 +673,13 @@ mod tests {
         )
         "#);
     }
+
+    #[test]
+    fn check_empty_output() {
+        let input = "{{ if foo }}{{ end }}";
+
+        let parsed = crate::parser::parse(input.into()).unwrap();
+
+        panic_pretty(input, parse(parsed.tokens()));
+    }
 }

src/ast/snapshots/nomo__ast__tests__simple_if_ast.snap

@@ -16,6 +16,8 @@ TemplateAst {
                             [Whitespace]"\n            " (12..25),
                         ),
                     },
+                },
+                ConditionalContent {
                     content: [
                         ConditionalChain {
                             chain: [
@@ -29,6 +31,8 @@ TemplateAst {
                                             [Whitespace]"\n                " (37..54),
                                         ),
                                     },
+                                },
+                                ConditionalContent {
                                     content: [
                                         StaticContent(
                                             [Content]"Hiii" (54..58),

src/emit/mod.rs

@@ -92,7 +92,6 @@ fn emit_ast_expr(
             let mut chain = chain.iter();
             let Some(TemplateAstExpr::IfConditional {
                 if_block: expression,
-                content,
             }) = chain.next()
             else {
                 unreachable!("First element in conditional chain should be an IfConditional");
@@ -107,6 +106,10 @@ fn emit_ast_expr(
                 unreachable!("The end of an IfConditional must be a Block");
             };
 
+            let Some(TemplateAstExpr::ConditionalContent { content }) = chain.next() else {
+                unreachable!("The end of an IfConditional must be a Block");
+            };
+
             if let Some(ws) = prev_whitespace_content {
                 eval.push(Instruction::AppendContent {
                     content: ws.source().clone(),
@@ -163,6 +166,7 @@ fn emit_ast_expr(
         TemplateAstExpr::Block { .. }
         | TemplateAstExpr::EndBlock
         | TemplateAstExpr::IfConditional { .. }
+        | TemplateAstExpr::ConditionalContent { .. }
         | TemplateAstExpr::ElseConditional { .. }
         | TemplateAstExpr::Invalid { .. }
         | TemplateAstExpr::VariableAccess { .. } => eval.push(Instruction::Abort),
@@ -191,6 +195,7 @@ fn emit_expr_load(
         TemplateAstExpr::EndBlock => todo!(),
         TemplateAstExpr::Block { .. } => todo!(),
         TemplateAstExpr::IfConditional { .. } => todo!(),
+        TemplateAstExpr::ConditionalContent { .. } => todo!(),
     }
 }
 

tests/cases/2-ast@condition.snap

@@ -17,6 +17,8 @@ TemplateAst {
                             [Whitespace]"\n    " (13..18),
                         ),
                     },
+                },
+                ConditionalContent {
                     content: [
                         StaticContent(
                             [Content]"Hello World!" (18..30),