diff --git a/docs/grammar.txt b/docs/grammar.txt
index 9f4bf55db..06b306499 100644
--- a/docs/grammar.txt
+++ b/docs/grammar.txt
@@ -24,10 +24,12 @@ StructDefinition = 'struct' Identifier '{'
 ModifierDefinition = 'modifier' Identifier ParameterList?  ( 'virtual' | OverrideSpecifier )* Block
 ModifierInvocation = Identifier ( '(' ExpressionList? ')' )?
 
-FunctionDefinition = 'function' Identifier? ParameterList
+FunctionDefinition = FunctionDescriptor ParameterList
                      ( ModifierInvocation | StateMutability | 'external' | 'public' | 'internal' | 'private' | 'virtual' | OverrideSpecifier )*
                      ( 'returns' ParameterList )? ( ';' | Block )
 
+FunctionDescriptor = 'function' Identifier | 'constructor' | 'fallback' | 'receive'
+
 OverrideSpecifier = 'override' ( '(' UserDefinedTypeName (',' UserDefinedTypeName)* ')' )?
 
 EventDefinition = 'event' Identifier EventParameterList 'anonymous'? ';'