Disallow decimals without leading and trailing digits, enforce subscript indentation

Author: rattrayalex

src/parser/expression.js

@@ -363,13 +363,39 @@ pp.parseSubscripts = function (base, startPos, startLoc, noCalls) {
       node.object = base;
       node.callee = this.parseNoCallExpr();
       return this.parseSubscripts(this.finishNode(node, "BindExpression"), startPos, startLoc, noCalls);
-    } else if (this.eat(tt.dot)) {
+    } else if (this.match(tt.dot)) {
+      // require indentation
+      if (this.hasPlugin("lightscript") && this.isNonIndentedBreakFrom(startPos)) {
+        if (this.lookahead().type === tt.num) {
+          this.unexpected(null, "Either indent for array access or use a leading zero for a decimal.");
+        }
+        this.unexpected(null, "Indentation required.");
+      }
+
+      // catch malformed decimals (but allow `0.0.toString()`, which is actually valid)
+      if (this.hasPlugin("lightscript") && base.type === "NumericLiteral") {
+        if (!(base.extra && base.extra.raw && base.extra.raw.match(/\./))) {
+          this.unexpected(null, "Numbers with a decimal must end in a number (eg; `1.0`) in LightScript.");
+        }
+      }
+
+      this.next();
       const node = this.startNodeAt(startPos, startLoc);
       node.object = base;
-      node.property = this.parseIdentifier(true);
-      node.computed = false;
+
+      // parse arr.0 as arr[0]
+      if (this.hasPlugin("lightscript") && this.match(tt.num)) {
+        node.property = this.parseExprAtom();
+        node.computed = true;
+      } else {
+        node.property = this.parseIdentifier(true);
+        node.computed = false;
+      }
       base = this.finishNode(node, "MemberExpression");
     } else if (this.hasPlugin("lightscript") && this.match(tt.elvis)) {
+      if (this.isNonIndentedBreakFrom(startPos)) {
+        this.unexpected(null, "Indentation required.");
+      }
       // `x?.y`
       const node = this.startNodeAt(startPos, startLoc);
       const op = this.state.value;
@@ -392,7 +418,11 @@ pp.parseSubscripts = function (base, startPos, startLoc, noCalls) {
         this.unexpected();
       }
       base = this.finishNode(node, "SafeMemberExpression");
-    } else if (this.hasPlugin("lightscript") && !noCalls && this.eat(tt.tilde)) {
+    } else if (this.hasPlugin("lightscript") && !noCalls && this.match(tt.tilde)) {
+      if (this.isNonIndentedBreakFrom(startPos)) {
+        this.unexpected(null, "Indentation required.");
+      }
+      this.next();
       const node = this.startNodeAt(startPos, startLoc);
       node.left = base;
       // allow `this`, Identifier or MemberExpression, but not calls
@@ -402,13 +432,6 @@ pp.parseSubscripts = function (base, startPos, startLoc, noCalls) {
       this.expect(tt.parenL);
       node.arguments = this.parseCallExpressionArguments(tt.parenR, false);
       base = this.finishNode(node, "TildeCallExpression");
-    } else if (this.hasPlugin("lightscript") && this.isNumberStartingWithDot() && !this.isNonIndentedBreakFrom(startPos)) {
-      // parses x.0, x.1, etc, as x[0], x[1], etc.
-      const node = this.startNodeAt(startPos, startLoc);
-      node.object = base;
-      node.property = this.parseNumericLiteralMember();
-      node.computed = true;
-      base = this.finishNode(node, "MemberExpression");
     } else if (!(this.hasPlugin("lightscript") && this.isNonIndentedBreakFrom(startPos)) && this.eat(tt.bracketL)) {
       const node = this.startNodeAt(startPos, startLoc);
       node.object = base;
@@ -712,6 +735,11 @@ pp.parseExprAtom = function (refShorthandDefaultPos) {
         this.unexpected(null, "Unmatched `else` (must match indentation of the line with `if`).");
       }
 
+    case tt.dot:
+      if (this.hasPlugin("lightscript") && this.lookahead().type === tt.num) {
+        this.unexpected(null, "Decimal numbers must be prefixed with a `0` in LightScript (eg; `0.1`).");
+      }
+
     default:
       this.unexpected();
   }

src/plugins/lightscript.js

@@ -134,41 +134,6 @@ pp.parseObjectComprehension = function(node) {
   return this.finishNode(node, "ObjectComprehension");
 };
 
-pp.isNumberStartingWithDot = function () {
-  return (
-    this.match(tt.num) &&
-    this.state.input.charCodeAt(this.state.start) === 46  // "."
-  );
-};
-
-// the tokenizer reads dots directly into numbers,
-// so "x.1" is tokenized as ["x", .1] not ["x", ".", 1]
-// therefore, we have to hack, reading the number back into a string
-// and parsing out the dot.
-
-pp.parseNumericLiteralMember = function () {
-  // 0.1 -> 1, 0 -> 0
-  let numStr = String(this.state.value);
-  if (numStr.indexOf("0.") === 0) {
-    numStr = numStr.slice(2);
-  } else if (numStr !== "0") {
-    this.unexpected();
-  }
-  const num = parseInt(numStr, 10);
-
-  // must also remove "." from the "raw" property,
-  // b/c that's what's inserted in code
-
-  const node = this.parseLiteral(num, "NumericLiteral");
-  if (node.extra.raw.indexOf(".") === 0) {
-    node.extra.raw = node.extra.raw.slice(1);
-  } else {
-    this.unexpected();
-  }
-
-  return node;
-};
-
 // c/p parseBlock
 
 pp.parseWhiteBlock = function (allowDirectives?, isExpression?) {

src/tokenizer/index.js

@@ -297,7 +297,8 @@ export default class Tokenizer {
   //
   readToken_dot() {
     const next = this.input.charCodeAt(this.state.pos + 1);
-    if (next >= 48 && next <= 57) {
+    // in lightscript, numbers cannot start with a naked `.`
+    if (next >= 48 && next <= 57 && !this.hasPlugin("lightscript")) {
       return this.readNumber(true);
     }
 
@@ -688,9 +689,14 @@ export default class Tokenizer {
     const octal = this.input.charCodeAt(this.state.pos) === 48;
     let isFloat = false;
 
+    // for numeric array access (eg; arr.0), don't read floats (numbers with a decimal).
+    const noFloatsAllowed = this.hasPlugin("lightscript") &&
+      this.state.tokens.length > 0 &&
+      this.state.tokens[this.state.tokens.length - 1].type === tt.dot;
+
     if (!startsWithDot && this.readInt(10) === null) this.raise(start, "Invalid number");
     let next = this.input.charCodeAt(this.state.pos);
-    if (next === 46) { // '.'
+    if (next === 46 && !noFloatsAllowed) { // '.'
       ++this.state.pos;
       this.readInt(10);
       isFloat = true;
@@ -702,6 +708,10 @@ export default class Tokenizer {
       if (this.readInt(10) === null) this.raise(start, "Invalid number");
       isFloat = true;
     }
+    // don't read the decimal if it's not followed by a number; `1.` is illegal, must do `1.0`
+    if (this.hasPlugin("lightscript") && this.input.charCodeAt(this.state.pos - 1) === 46) {
+      --this.state.pos;
+    }
     if (isIdentifierStart(this.fullCharCodeAtPos())) this.raise(this.state.pos, "Identifier directly after number");
 
     const str = this.input.slice(start, this.state.pos);

test/fixtures/core/uncategorised/319/options.lightscript.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Numbers with a decimal must end in a number (eg; `1.0`) in LightScript. (1:3)"
+}

test/fixtures/core/uncategorised/320/options.lightscript.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Numbers with a decimal must end in a number (eg; `1.0`) in LightScript. (1:3)"
+}

test/fixtures/core/uncategorised/542/options.lightscript.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Indentation required. (2:0)"
+}

test/fixtures/core/uncategorised/70/options.lightscript.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Decimal numbers must be prefixed with a `0` in LightScript (eg; `0.1`). (1:0)"
+}

test/fixtures/esprima/es2015-spread-element/call-spread-number/options.lightscript.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Decimal numbers must be prefixed with a `0` in LightScript (eg; `0.1`). (1:5)"
+}

test/fixtures/esprima/es2015-spread-element/new-spread-number/options.lightscript.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Decimal numbers must be prefixed with a `0` in LightScript (eg; `0.1`). (1:9)"
+}

test/fixtures/lightscript/automatic-semicolon-insertion/dot-access/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Indentation required. (2:0)"
+}