Merge pull request #1397 from DanielXMoore/break-continue-with-2

`break/continue [label] with` and better error handling

civet.dev/reference.md

@@ -1744,6 +1744,16 @@ found :=
     process item
 </Playground>
 
+<Playground>
+function process(lists)
+  :outer for list of lists
+    for item of list
+      if item is "abort"
+        break outer with item
+      if item is "length"
+        continue :outer with list.length
+</Playground>
+
 ## Other Blocks
 
 ### Try Blocks

source/parser.hera

@@ -4224,7 +4224,11 @@ LabelledStatement
 Label
   # NOTE: `:label` instead of `label:` to not clash with implicit object literal
   Colon:colon Identifier:id Whitespace:w ->
-    return [ id, colon, w ]
+    return {
+      type: "Label",
+      name: id.name,
+      children: [ id, colon, w ]
+    }
 
 # Argument to break/continue, which can include colon or not in input,
 # but should not have colon in output
@@ -5049,10 +5053,18 @@ KeywordStatement
   # https://262.ecma-international.org/#prod-BreakStatement
   # NOTE: Also allow `break :label` for symmetry
   Break ( _ LabelIdentifier )? ( _ With MaybeNestedExtendedExpression )? ->
+    const children = [ $1 ]
+    if ($2) children.push($2)
+    if ($3) children.push({
+      type: "Error",
+      subtype: "Warning",
+      message: "'break with' outside of loop that returns a value",
+    })
     return {
       type: "BreakStatement",
+      label: $2?.[1],
       with: $3?.[2],
-      children: [ $1, $2 ],
+      children,
     }
 
   # NOTE: `continue switch` for fallthrough
@@ -5066,10 +5078,18 @@ KeywordStatement
   # https://262.ecma-international.org/#prod-ContinueStatement
   # NOTE: Also allow `continue :label` for symmetry
   Continue ( _ LabelIdentifier )? ( _ With MaybeNestedExtendedExpression )? ->
+    const children = [ $1 ]
+    if ($2) children.push($2)
+    if ($3) children.push({
+      type: "Error",
+      subtype: "Warning",
+      message: "'continue with' outside of loop that returns a value",
+    })
     return {
       type: "ContinueStatement",
+      label: $2?.[1],
       with: $3?.[2],
-      children: [ $1, $2 ],
+      children,
     }
 
   DebuggerStatement

source/parser/function.civet

@@ -5,17 +5,16 @@ import type {
   BlockStatement
   BreakStatement
   CallExpression
-  ContinueStatement
-  Declaration
   ForStatement
   FunctionNode
   IterationExpression
   IterationFamily
   IterationStatement
-  LabeledStatement
+  LabelledStatement
   Parameter
   ParametersNode
   StatementTuple
+  SwitchStatement
   TypeIdentifierNode
   TypeNode
   Whitespace
@@ -269,7 +268,7 @@ function assignResults(node: StatementTuple[] | ASTNode, collect: (node: ASTNode
   outer := exp
   {type} .= exp
   if type is "LabelledStatement"
-    exp = (exp as LabeledStatement).statement
+    exp = exp.statement
     {type} = exp
 
   switch type
@@ -370,7 +369,7 @@ function insertReturn(node: ASTNode, outerNode: ASTNode = node): void
   outer := exp
   {type} .= exp
   if type is "LabelledStatement"
-    exp = (exp as LabeledStatement).statement
+    exp = exp.statement
     {type} = exp
 
   switch type
@@ -447,16 +446,13 @@ function insertSwitchReturns(exp): void
   exp.caseBlock.clauses.forEach (clause) =>
     insertReturn clause
 
-// Process `break with` and `continue with` within a loop
+// Process `break with` and `continue with` within a loop statement
 // that already has a resultsRef attribute.
 // Returns whether the resultsRef might be modified, so should use let.
 function processBreakContinueWith(statement: IterationStatement | ForStatement): boolean
   changed .= false
-  for control of gatherRecursive(statement.block,
-    (s: ASTNodeObject): s is BreakStatement | ContinueStatement =>
-      s.type is like "BreakStatement", "ContinueStatement"
-    (s: ASTNodeObject) =>
-      isFunction(s) or s.type is "IterationStatement"
+  for control of gatherRecursiveWithinFunction(statement.block,
+    .type is "BreakStatement" or .type is "ContinueStatement"
   )
     function controlName: string
       switch control.type 
@@ -468,6 +464,21 @@ function processBreakContinueWith(statement: IterationStatement | ForStatement):
     // break with <expr> overwrites the results of the loop
     // continue with <expr> appends to the results of the loop
     if control.with
+      if control.label
+        continue unless statement.parent is like {
+          type: "LabelledStatement"
+          label: { name: ^control.label.name }
+        }
+      else
+        // Verify there wasn't another loop or switch in between
+        {ancestor} := findAncestor control,
+          (s: ASTNodeObject): s is IterationStatement | ForStatement | SwitchStatement => (or)
+            s is statement
+            s.type is "IterationStatement"
+            s.type is "ForStatement"
+            s.type is "SwitchStatement" and control.type is "BreakStatement"
+        continue unless ancestor is statement
+
       control.children.unshift
         if control.type is "BreakStatement"
           changed = true
@@ -476,6 +487,10 @@ function processBreakContinueWith(statement: IterationStatement | ForStatement):
           [statement.resultsRef, '.push(', trimFirstSpace(control.with), ');']
       updateParentPointers control.with, control
 
+      // Remove warning associated with break/continue with
+      i := control.children.findIndex ?.type is "Error"
+      control.children.splice i, 1 if i >= 0
+
       // Brace containing block now that it has multiple statements
       block := control.parent
       unless block?.type is "BlockStatement"

source/parser/types.civet

@@ -24,7 +24,7 @@ export type StatementNode =
   | ForStatement
   | IfStatement
   | IterationStatement
-  | LabeledStatement
+  | LabelledStatement
   | ReturnStatement
   | SwitchStatement
   | ThrowStatement
@@ -79,6 +79,7 @@ export type OtherNode =
   | FinallyClause
   | Index
   | Initializer
+  | Label
   | ObjectBindingPattern
   | Parameter
   | ParametersNode
@@ -111,6 +112,7 @@ export type ASTWrapper =
 
 export type ASTError =
   type: "Error"
+  subtype?: "Warning" | "Error"
   message: string
   token?: undefined
   filename?: string
@@ -288,6 +290,7 @@ export type BreakStatement
   children: Children
   parent?: Parent
   with: ASTNode?
+  label: Label?
 
 export type ComptimeStatement
   type: "ComptimeStatement"
@@ -307,6 +310,7 @@ export type ContinueStatement
   parent?: Parent
   special?: "switch"
   with: ASTNode?
+  label: Label?
 
 export type DoStatement
   type: "DoStatement"
@@ -359,13 +363,19 @@ export type DefaultClause
   children: Children
   block: BlockStatement
 
-export type LabeledStatement
-  type: "LabeledStatement"
-  label: ASTNode
+export type LabelledStatement
+  type: "LabelledStatement"
+  label: Label
   statement: ASTNodeBase
   children: Children
   parent?: Parent
 
+export type Label
+  type: "Label"
+  children: Children
+  parent?: Parent
+  name: string
+
 export type AccessStart
   type: "AccessStart"
   children: Children

source/parser/util.civet

@@ -128,7 +128,7 @@ statementTypes := new Set [
   "ForStatement"
   "IfStatement"
   "IterationStatement"
-  "LabeledStatement"
+  "LabelledStatement"
   "ReturnStatement"
   "SwitchStatement"
   "ThrowStatement"

test/for.civet

@@ -782,15 +782,76 @@ describe "for", ->
     };const values =results
   """
 
-  testCase """
+  throws """
     break/continue with outside expression context
     ---
     for x of y
       continue with null unless x?
       break with x
     ---
-    for (const x of y) {
-      if (!(x != null)) { continue }
-      break
+    ParseErrors: unknown:2:11 'continue with' outside of loop that returns a value
+    unknown:3:8 'break with' outside of loop that returns a value
+  """
+
+  throws """
+    break with inside switch
+    ---
+    =>
+      for x of y
+        switch x
+          when 1
+            break with x
+    ---
+    ParseErrors: unknown:5:14 'break with' outside of loop that returns a value
+  """
+
+  testCase """
+    continue with inside switch
+    ---
+    =>
+      for x of y
+        switch x
+          when 1
+            continue with 0
+        x
+    ---
+    () => {
+      const results=[];for (const x of y) {
+        switch(x) {
+          case 1: { {
+            results.push(0);continue}
+          }
+        }
+        results.push(x)
+      };return results;
+    }
+  """
+
+  testCase """
+    labelled break/continue with
+    ---
+    function f(arrays)
+      :outer for array of arrays
+        :inner for item of array
+          break :outer with [] if item is "ABORT"
+          continue outer with [] if item is "SKIP"
+          break inner with [] if item is "abort"
+          continue :outer with [] if item is "skip"
+          break with [] if item is "abort"
+          continue with [] if item is "skip"
+          item * item
+    ---
+    function f(arrays) {
+      let results;results=[];outer: for (const array of arrays) {
+        let results1;results1=[];inner: for (const item of array) {
+          if (item === "ABORT") { results = [];break outer }
+          if (item === "SKIP") { results.push([]);continue outer }
+          if (item === "abort") { results1 = [];break inner }
+          if (item === "skip") { results.push([]);continue outer }
+          if (item === "abort") { results1 = [];break }
+          if (item === "skip") { results1.push([]);continue }
+          results1.push(item * item)
+        }results.push(results1)
+      };return results;
     }
   """