Compiler: Allow local variables in blocks #51

E.g. this code: [ | a | a := 1. a + 1 ] value.
Will return 2.

Author: FunctionPoint

Compiler/src/ClassCompiler.ts

@@ -204,7 +204,7 @@ export class ClassCompiler
 	{
 		while( !this.parser.atMethodEnd() ) {
 			this.compileConstructor();
-			this.compileLocalVariables();
+			this.compileMethodVariables();
 			this.compileStatements();
 		}
 
@@ -222,16 +222,16 @@ export class ClassCompiler
 		this.method.body.add( node );
 	}
 
-	private compileLocalVariables()
+	private compileMethodVariables()
 	{
 		if( !this.parser.tryParseTerm( "|" ) )
 			return;
 
 		while( !this.parser.tryParseTerm( "|" ) )
-			this.compileLocalVariable();
+			this.compileVariable();
 	}
 
-	private compileLocalVariable()
+	private compileVariable(): SourceNode
 	{
 		let variableName: string = this.parser.parseVariableName();
 
@@ -248,8 +248,10 @@ export class ClassCompiler
 		compiledVariable.node = this.sourceNode( source, "variable" );
 
 		this.method.vars.push( compiledVariable );
+		return compiledVariable.node;
 	}
 
+
 	private compileStatements()
 	{
 		while( !this.parser.atMethodEnd() ) {
@@ -379,18 +381,22 @@ export class ClassCompiler
 		let node = this.sourceNode( "stBlock$class.$fromJs$( " + asyncString + "( ", "block" );
 
 		let oldArgs = this.method.args.slice();
+		let oldVars = this.method.vars.slice();
 
 		if( this.parser.peekTerm() == ":" )
 			this.compileBlockArguments( node );
 
 		node.add( " ) => {\n" );
 
+		this.compileBlockVariables( node );
+
 		while( ! this.parser.tryParseTerm( "]" ) )
 			node.add( this.compileBlockStatement() );
 
 		node.add( "\t\t\t} )" );
 
 		this.method.args = oldArgs;
+		this.method.vars = oldVars;
 
 		this.addClassReferenceToClassAndMethod( "Block" );
 
@@ -416,6 +422,19 @@ export class ClassCompiler
 		this.parser.mustParseTerm( "|" );
 	}
 
+	// Parse block local variables and add them to method variables (temporarily).
+
+	compileBlockVariables( node: SourceNode )
+	{
+		if( !this.parser.tryParseTerm( "|" ) )
+			return;
+
+		while( !this.parser.tryParseTerm( "|" ) ) {
+			node.add( "\t\t" );
+			node.add( this.compileVariable() );
+		}
+	}
+
 	// A block statement consists of an expression,
 	// possibly preceded by the return operator "^".
 

Smalltalk/Core/Base/Object.st

@@ -11,7 +11,8 @@ CLASSMETHODS
 async myTest
 	"This is the first method compiled.
 	Can be changed when testing the compiler."
-	await 1 + 2.
+	| result |
+	result := [ | a | a := 1. a + 1 ] value.
 !
 
 "Creating"

Smalltalk/Core/Base/Test/TestBlock.st

@@ -16,6 +16,9 @@ test
 	num := 0.
 	[ num < 3 ]	whileTrue: [ num := num + 1 ].
 	self assert: [ num = 3 ].
+
+	num := [ | a | a := 1. a + 1 ] value.
+	self assert: [ num = 2 ].
 !
 async testValueAwait
 	| result |