Add initial support for const declaration

vpdb · Aug 19, 2019 · b51b03a · b51b03a
1 parent a11200c
commit b51b03a
Show file tree

Hide file tree

Showing 3 changed files with 57 additions and 3 deletions.
diff --git a/lib/scripting/estree.ts b/lib/scripting/estree.ts
@@ -17,7 +17,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
-import { Program, VariableDeclaration, VariableDeclarator } from 'estree';
+import { Literal, Program, VariableDeclaration, VariableDeclarator  } from 'estree';
 
 /**
  * Returns the root node.
@@ -49,3 +49,27 @@ export function variableDeclarator(name: string): VariableDeclarator {
 		id: { type: 'Identifier', name },
 	};
 }
+
+/**
+ * Returns a constant declaration.
+ */
+export function constDecl(data: any): VariableDeclaration {
+	const name: string = data[2][0];
+
+	return {
+		type: 'VariableDeclaration',
+		kind: 'const',
+		declarations: [ {
+			type: 'VariableDeclarator',
+			id: { type: 'Identifier', name },
+			init: literal(data[2][4]),
+		}],
+	};
+}
+
+export function literal(data: any): Literal {
+	return {
+		type: 'Literal',
+		value: data,
+	};
+}
diff --git a/lib/scripting/transpile.spec.ts b/lib/scripting/transpile.spec.ts
@@ -28,4 +28,10 @@ describe('The VBScript transpiler', () => {
 		const js = vbsToJs(vbs);
 		expect(js).to.equal('let test1, test2, test3;\n');
 	});
+
+	it('should transpile a const declaration', () => {
+		const vbs = `Const pi = 3.14\n`;
+		const js = vbsToJs(vbs);
+		expect(js).to.equal('const pi = 3.14;\n');
+	});
 });
diff --git a/lib/scripting/vbscript.ne b/lib/scripting/vbscript.ne
@@ -1,4 +1,5 @@
 @builtin "whitespace.ne"
+@builtin "number.ne"
 
 @{%
 const estree = require('./estree');
@@ -7,9 +8,9 @@ const estree = require('./estree');
 Program              -> NLOpt GlobalStmt:*                           {% data => estree.program(data[1]) %}
 
 GlobalStmt           -> OptionExplicit
+                      | ConstDecl                                    {% data => data[0] %}
                       | BlockStmt                                    {% data => data[0] %}
 
-
 OptionExplicit       -> "Option" __ "Explicit" NL
 
 BlockStmt            -> VarDecl                                      {% data => data[0] %}
@@ -33,9 +34,30 @@ SafeKeywordID        -> "Default"
 ID                   -> Letter IDTail                                {% data => data[0] + data[1] %}
                       | "[" IDNameChar:* "]"
 
-ArrayRankList        -> IntLiteral "," ArrayRankList
+ArrayRankList        -> IntLiteral _ "," _ ArrayRankList
                       | IntLiteral
 
+ConstDecl            -> AccessModifierOpt __ "Const" __ ConstList NL
+                      | "Const" __ ConstList NL                      {% estree.constDecl %}
+
+ConstList            -> ExtendedID _ "=" _ ConstExprDef _ "," _ ConstList
+                      | ExtendedID _ "=" _ ConstExprDef
+
+ConstExprDef         -> "(" _ ConstExprDef _ ")"
+                      | "-" _ ConstExprDef
+                      | "+" _ ConstExprDef
+                      | ConstExpr                                    {% data => data[0] %}
+
+AccessModifierOpt    -> "Public"
+                      | "Private"
+
+ConstExpr            -> FloatLiteral                                 {% data => data[0] %}
+                      | Nothing                                      {% data => data[0] %}
+
+Nothing              -> "Nothing"
+                      | "Null"
+                      | "Empty"
+
 NLOpt                -> NL:*
 
 NL                   -> NewLine NL
@@ -50,6 +72,8 @@ IntLiteral           -> DecDigit:+
                       | HexLiteral
                       | OctLiteral
 
+FloatLiteral         -> decimal                                    {% data => data[0] %}  # DecDigit:* "." DecDigit:+ ( "E" [+-]:? DecDigit:+ ):?
+
 HexLiteral           -> "&H" HexDigit:+ "&":?
 OctLiteral           -> "&" OctDigit:+ "&":?