Parse conditional access

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

src/compiler/mod.rs

@@ -1,9 +1,9 @@
 use std::collections::BTreeMap;
 
-use crate::parser::TemplateAstExpr;
 use crate::input::NomoInput;
 use crate::lexer::TemplateToken;
 use crate::lexer::TokenOperator;
+use crate::parser::TemplateAstExpr;
 use crate::value::NomoValue;
 
 pub struct EmitMachine {
@@ -424,6 +424,7 @@ fn emit_ast_expr(
         | TemplateAstExpr::Literal { .. }
         | TemplateAstExpr::FunctionCall { .. }
         | TemplateAstExpr::Operation { .. }
+        | TemplateAstExpr::ConditionalAccess { .. }
         | TemplateAstExpr::VariableAccess { .. } => eval.push(Instruction::Abort),
     }
 }
@@ -475,6 +476,7 @@ fn emit_expr_load(
                 slot: emit_slot,
             });
         }
+        TemplateAstExpr::ConditionalAccess { .. } => todo!(),
         TemplateAstExpr::Invalid { .. } => eval.push(Instruction::Abort),
         TemplateAstExpr::StaticContent { .. } | TemplateAstExpr::Interpolation { .. } => {
             unreachable!("Invalid AST here")

src/parser/mod.rs

@@ -2,6 +2,7 @@ use thiserror::Error;
 use winnow::Parser;
 use winnow::RecoverableParser;
 use winnow::combinator::Infix::Left;
+use winnow::combinator::Postfix;
 use winnow::combinator::alt;
 use winnow::combinator::cut_err;
 use winnow::combinator::delimited;
@@ -249,6 +250,7 @@ pub enum TemplateAstExpr<'input> {
         value_expression: Box<TemplateAstExpr<'input>>,
     },
     ForElse,
+    ConditionalAccess(TemplateToken),
     VariableAccess(TemplateToken),
     IfConditional {
         expression: Box<TemplateAstExpr<'input>>,
@@ -709,6 +711,16 @@ fn parse_expression<'input>(
                 Left Lesser => 15,
                 Left LesserOrEqual => 15,
             ]
+        }).postfix(dispatch! { surrounded(ws, parse_operator);
+            TokenOperator::QuestionMark => Postfix(22, |input, rhs| {
+                match rhs {
+                    TemplateAstExpr::VariableAccess(access) => Ok(TemplateAstExpr::ConditionalAccess(access)),
+                    _ => Err(AstError::from_input(input)),
+                }
+
+
+            }),
+            _ => fail
         }),
     )
     .parse_next(input)
@@ -1048,4 +1060,15 @@ mod tests {
 
         insta::assert_debug_snapshot!(ast);
     }
+
+    #[test]
+    fn check_conditional_access() {
+        let input = "{{= foo? }}";
+
+        let parsed = crate::lexer::parse(input.into()).unwrap();
+
+        let ast = panic_pretty(input, parse(parsed.tokens()));
+
+        insta::assert_debug_snapshot!(ast);
+    }
 }

src/parser/snapshots/nomo__parser__tests__check_conditional_access.snap

@@ -0,0 +1,15 @@
+---
+source: src/parser/mod.rs
+expression: ast
+---
+TemplateAst {
+    root: [
+        Interpolation {
+            prev_whitespace_content: None,
+            expression: ConditionalAccess(
+                [Ident]"foo" (4..7),
+            ),
+            post_whitespace_content: None,
+        },
+    ],
+}