fix: Support destructuring assignments in table expressions.

uwdata · Nov 17, 2020 · c2935d2 · c2935d2
1 parent e3da21e
commit c2935d2
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Showing 4 changed files with 47 additions and 1 deletion.
diff --git a/src/expression/ast/constants.js b/src/expression/ast/constants.js
@@ -1,3 +1,4 @@
+export const ArrayPattern = 'ArrayPattern';
 export const ArrowFunctionExpression = 'ArrowFunctionExpression';
 export const FunctionExpression = 'FunctionExpression';
 export const Identifier = 'Identifier';

diff --git a/src/expression/codegen.js b/src/expression/codegen.js
@@ -87,6 +87,9 @@ const visitors = {
   FunctionExpression: func,
   FunctionDeclaration: func,
 
+  ArrayPattern: (node, opt) => {
+    return '[' + list(node.elements, opt) + ']';
+  },
   ObjectPattern: (node, opt) => {
     return '{' + list(node.properties, opt) + '}';
   },

diff --git a/src/expression/parse.js b/src/expression/parse.js
@@ -1,6 +1,7 @@
 import { parse } from 'acorn';
 
 import {
+  ArrayPattern,
   ArrowFunctionExpression,
   Column,
   Constant,
@@ -176,6 +177,18 @@ function updateConstantNode(node, name) {
   node.raw = constants[name];
 }
 
+function handleDeclaration(node, ctx) {
+  if (is(Identifier, node)) {
+    ctx.scope.add(node.name);
+  } else if (is(ArrayPattern, node)) {
+    node.elements.forEach(elm => handleDeclaration(elm, ctx));
+  } else if (is(ObjectPattern, node)) {
+    node.properties.forEach(prop => handleDeclaration(prop.value, ctx));
+  } else {
+    ctx.error('Unsupported variable declaration', node.id);
+  }
+}
+
 const visitors = {
   FunctionDeclaration: parseError('Function definitions not allowed'),
   ForStatement: parseError('For loops not allowed'),
@@ -191,7 +204,7 @@ const visitors = {
   UpdateExpression: parseError('Updates not allowed'),
 
   VariableDeclarator(node, ctx) {
-    ctx.scope.add(node.id.name);
+    handleDeclaration(node.id, ctx);
   },
   Identifier(node, ctx, parent) {
     if (handleIdentifier(node, ctx, parent) && !ctx.scope.has(node.name)) {

diff --git a/test/expression/parse-test.js b/test/expression/parse-test.js
@@ -279,6 +279,35 @@ tape('parse parses expressions with switch statements', t => {
   t.end();
 });
 
+tape('parse parses expressions with destructuring assignments', t => {
+  const exprs = {
+    arr: () => {
+      const [start, stop, step] = op.bins('value');
+      return op.bin('value', start, stop, step);
+    },
+    obj: () => {
+      const { start, stop, step } = op.bins('value');
+      return op.bin('value', start, stop, step);
+    },
+    nest: () => {
+      const { start: [{ baz: bop }], stop, step } = op.bins('value');
+      return op.bin('value', bop, stop, step);
+    }
+  };
+
+  t.deepEqual(
+    parse(exprs, { compiler }).values,
+    {
+      arr: '{const [start,stop,step]=op[0];return fn.bin(\'value\',start,stop,step);}',
+      obj: '{const {start:start,stop:stop,step:step}=op[0];return fn.bin(\'value\',start,stop,step);}',
+      nest: '{const {start:[{baz:bop}],stop:stop,step:step}=op[0];return fn.bin(\'value\',bop,stop,step);}'
+    },
+    'parsed destructuring assignmeents'
+  );
+
+  t.end();
+});
+
 tape('parse throws on expressions with for loops', t => {
   const exprs = {
     val: () => {