Added new grammar for try/catch + let else

khonsulabs · Feb 13, 2024 · ee875f8 · ee875f8
1 parent f7a3baa
commit ee875f8
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Showing 3 changed files with 20 additions and 6 deletions.
diff --git a/guide/src/reference.md b/guide/src/reference.md
@@ -92,7 +92,8 @@ Prefix:
         Continue |
         Break |
         Return |
-        Match> | Term;
+        Match |
+        Try> | Term;
 
 Literal: 'true' | 'false';
 
@@ -121,8 +122,10 @@ ArrowBody: '=>' <Expression>;
 BlockBody: '{' <Chain> '}';
 FnMatch: '{' <MatchBody> '}';
 
-Let: 'let' <Pattern> '=' <Expression>;
-Var: 'var' <Pattern> '=' <Expression>;
+Let: 'let' <VariablePattern>;
+Var: 'var' <VariablePattern>;
+VariablePattern: <GuardedPattern> '=' <Expression> <VariableElse>?;
+VariableElse: 'else' <Expression>;
 
 If: 'if' <Expression> <ThenExpression | Block> <ElseExpression>?;
 ThenExpression: 'then' <Expression>;
@@ -138,7 +141,8 @@ Continue: 'continue' <Label>?;
 Break: 'break' <Label>? <Expression>?;
 Return: 'return' <Expression>?;
 
-Match: 'match' <Expression> '{' <MatchBody> '}';
+Match: 'match' <Expression> <MatchBlock>;
+MatchBlock: '{' <MatchBody> '}';
 MatchBody: (<MatchPattern> (',' <MatchPattern>)*)?;
 MatchPattern: <GuardedPattern> '=>' <Expression>;
 GuardedPattern: <Pattern> ('if' <Expression>)?;
@@ -147,5 +151,9 @@ IdentifierPattern: '_' | <Identifier>;
 TuplePattern: '(' (<Pattern> (',' <Pattern>)*)? ')';
 ListPattern: '[' (<Pattern> (',' <Pattern>)*)? ']';
 
+Try: 'try' <Expression> ('catch' <MatchBlock | SingleCatch | ArrowCatch>)?;
+SingleCatch: <GuardedPattern> <Block>;
+ArrowCatch: '=>' <Expression>;
+
 Term: <Identifier | Number | Regex | String | Symbol>;
 ```
diff --git a/guide/src/reference/assignment.md b/guide/src/reference/assignment.md
@@ -3,6 +3,8 @@
 ```musebnf
 Assignment: <Lookup | Index> ('=' <Assignment>)*;
 
-Let: 'let' <Pattern> '=' <Expression>;
-Var: 'var' <Pattern> '=' <Expression>;
+Let: 'let' <VariablePattern>;
+Var: 'var' <VariablePattern>;
+VariablePattern: <GuardedPattern> '=' <Expression> <VariableElse>?;
+VariableElse: 'else' <Expression>;
 ```
diff --git a/guide/src/reference/errors.md b/guide/src/reference/errors.md
@@ -3,4 +3,8 @@
 ```musebnf
 TryOperator: '?' <Punctuation>?;
 NilCoalesce: '??' <Punctuation>;
+
+Try: 'try' <Expression> ('catch' <MatchBlock | SingleCatch | ArrowCatch>)?;
+SingleCatch: <GuardedPattern> <Block>;
+ArrowCatch: '=>' <Expression>;
 ```