8127312101

Committed 03 Mar 2024 02:57AM UTC coverage: 91.895% (+0.03%) from 91.868%

Build # 8127312101

Build Type

Pull #1077

github

Committed by

web-flow

Commit Message

Merge 37498f7d4 into aa6945014

Pull Request Pull Request #1077: Wip if statement expressions

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96.91

/source/parser/lib.civet

/**
 * lib.civet holds functions that are used inside parser.hera
 *
 * The rules inside parser.hera should be simple and short.
 * Most of the helpers/transforms should make their way into
 * here eventually.
 */

import type {
  ASTNode
  ASTNodeBase
  BlockStatement
  DoStatement
  ForStatement
  IfStatement
  IterationStatement
  MethodDefinition
  ParseRule
  StatementExpression
  StatementTuple
  WSNode
} from ./types.civet

import {
  gatherRecursive
  gatherRecursiveAll
} from ./traversal.civet

import {
  addParentPointers
  assert
  deepCopy
  getTrimmingSpace
  hasAwait
  hasYield
  insertTrimmingSpace
  isComma
  isEmptyBareBlock
  isWhitespaceOrEmpty
  literalValue
  makeAmpersandFunction
  makeLeftHandSideExpression
  makeNode
  makeRef
  maybeRef
  parenthesizeType
  wrapIIFE
  wrapWithReturn
} from ./util.civet

import {
  blockWithPrefix
  duplicateBlock
  hoistRefDecs
  makeEmptyBlock
  processBlocks
} from ./block.civet

import {
  processAssignmentDeclaration
  processDeclarationConditions
  processDeclarations
} from ./declaration.civet

import { processPipelineExpressions } from ./pipe.civet
import { forRange, processForInOf } from ./for.civet
import {
  processFunctions
  expressionizeIteration
  skipImplicitArguments
} from ./function.civet
import { processPatternMatching } from ./pattern-matching.civet
import {
  adjustAtBindings
  adjustBindingElements
  gatherBindingCode
} from ./binding.civet
import {
  getPrecedence
  precedenceStep
  processBinaryOpExpression
} from ./op.civet
import { processUnaryExpression } from ./unary.civet
import { createConstLetDecs, createVarDecs } from ./auto-dec.civet

import {
  dedentBlockString
  dedentBlockSubstitutions
  getIndentLevel
  modifyString
  processCoffeeInterpolation
  quoteString
} from ./string.civet

function addPostfixStatement(statement: StatementTuple, ws: ASTNode, post)
  expressions := [
    ...post.blockPrefix or []
    ["", statement]
  ]

  block := makeNode {
    type: "BlockStatement"
    children: [" { ", expressions, " }"]
    expressions
  }

  children := [...post.children, block]

  // This removes trailing whitespace for easier testing
  if (!isWhitespaceOrEmpty(ws)) children.push(ws)

  post = makeNode { ...post, children, block }
  if post.type is "IfStatement"
    post.then = block
  return post

// Negate expression inside condition
function negateCondition(condition)
  { expression } .= condition
  children := condition.children.slice()
  i := children.indexOf(expression)
  if i < 0
    throw new Error `Could not find expression in condition`
  children[i] = expression =
    type: "UnaryExpression"
    children: [
      "!"
      makeLeftHandSideExpression expression
    ]
  { ...condition, expression, children }

function isExpression(node: ASTNode): boolean
  if Array.isArray(node)
    return node.every(isExpression)

  if typeof node is "string"
    // TODO: may not quite be correct
    return true

  switch node.type
    case "BlockStatement"
    case "DebuggerStatement"
    case "IfStatement"
    case "IterationStatement"
    case "ReturnStatement"
    case "SwitchStatement"
    case "ThrowStatement"
    case "TryStatement"
      return false

  return true

function expressionizeBlock(blockOrExpression: ASTNode)
  if { expressions } := blockOrExpression
    l := expressions.length
    results := []

    for [ws, s, _delim], i of expressions
      if (!isExpression(s)) return
      wrapped := makeLeftHandSideExpression s
      if i is l - 1
        results.push [ws, wrapped]
      else
        results.push [ws, wrapped, ","]

    if results.length > 1
      return makeLeftHandSideExpression results

    return results
  else
    blockOrExpression

function expressionizeIfStatement(statement: IfStatement)
  { condition, then: b, else: e } := statement
  [ ...condRest, closeParen ] := condition.children  // separate ')'

  expressionizedBlock := expressionizeBlock b

  unless expressionizedBlock
    return wrapIIFE([["", statement]])

  children := [
    ...condRest
    "?"
    expressionizedBlock
  ]
  if e
    e2 := expressionizeBlock(e[2])
    unless e2
      return wrapIIFE([["", statement]])

    // Replace 'else' in e[1] with ':'. (e[0] is space before 'else')
    children.push e[0], ":", e2, ...e[3..]
  else
    children.push ":void 0"
  children.push closeParen

  {
    type: "IfExpression",
    children,
  }

function expressionizeTypeIf([ws, ifOp, condition, t, e])
  children := [
    ws
    "("
    insertTrimmingSpace condition, ""
    "?"
  ]
  unless ifOp.negated xor condition.negated // if
    children.push t
    if e
      // Replace 'else' in e[1] with ':'. (e[0] is space before 'else')
      children.push e[0], ":", ...e[2..]
    else
      children.push ":never"
  else // unless
    if e
      children.push ...e[2..], e[0], ":"
    else
      children.push "never:"
    children.push t
  children.push ")"
  children

/**
 * This adjusts #x.y().z and @x.y().z when used inside Object glob expressions
 * to remove `this.` where necessary.
 *
 * [See More](../test/object.civet)
 */
function handleThisPrivateShorthands(value)
  if value.privateShorthand
    value = value.children[1].children[1]

    return [value, false]

  if value.type is "MemberExpression" or value.type is "CallExpression"
    suppressPrefix .= value.thisShorthand
    value = {
      ...value,
      children: value.children.map (c, i) =>
        if i is 0
          let s
          [c, s] = handleThisPrivateShorthands c
          suppressPrefix ||= s

        c
    }

    return [value, suppressPrefix]

  return [value, value.thisShorthand]

/**
 * Process globs, bind shorthand, and call shortcuts, in Call/MemberExpression
 */
function processCallMemberExpression(node)
  { children } := node

  // Parenthesized operator like (+), immediately called, expands to
  // use of the operator. This is useful for e.g. shortcutting (&&).
  if children[0]?.parenthesizedOp?.token and children[1]?.type is "Call"
    op := children[0].parenthesizedOp
    call .= children[1]
    args := [...call.args] // shallow copy
    call = { ...call, args }
    // Remove trailing comma
    if comma := isComma args.-1
      comma.token = ''
    // Arguments already start and end with open and close parentheses.
    // Replace each comma with an instance of the operator and matching parens.
    commaCount .= 0
    for each arg of args
      if comma := isComma arg
        comma.token = `)${op.token}(`
        commaCount++
    // Don't mess with (+)()
    if args.length
      children.splice 0, 2,
        commaCount ?
          type: "ParenthesizedExpression",
          children: ["(", call, ")"]
        : { ...call, type: "ParenthesizedExpression" }

  // Process globs and bind shorthand
  for (let i = 0; i < children.length; i++) {
    const glob = children[i]
    if (glob?.type is "PropertyGlob") {
      let prefix = children.slice(0, i)
      const parts = []
      let hoistDec, refAssignment
      // add ref to ensure object base evaluated only once
      if (prefix.length > 1) {
        const ref = makeRef()
        hoistDec = {
          type: "Declaration",
          children: ["let ", ref],
          names: [],
        }
        refAssignment = [{
          type: "AssignmentExpression",
          children: [ref, " = ", prefix],
        }, ","]
        prefix = [ref]
      }
      prefix = prefix.concat(glob.dot)

      for (const part of glob.object.properties) {
        if part.type is "MethodDefinition"
          throw new Error("Glob pattern cannot have method definition")
        if part.value and !["CallExpression", "MemberExpression", "Identifier"].includes(part.value.type)
          throw new Error(`Glob pattern must have call or member expression value, found ${JSON.stringify(part.value)}`)

        suppressPrefix .= false
        value .= part.value ?? part.name
        wValue := getTrimmingSpace part.value

        [value, suppressPrefix] = handleThisPrivateShorthands value

        if !suppressPrefix // Don't prefix @ shorthand
          value = prefix.concat(insertTrimmingSpace(value, ""))
        if (wValue) value.unshift(wValue)
        if (part.type is "SpreadProperty") {
          parts.push({
            type: part.type,
            value,
            dots: part.dots,
            delim: part.delim,
            names: part.names,
            children: part.children.slice(0, 2) // whitespace, ...
              .concat(value, part.delim)
          })
        } else {
          parts.push({
            type: part.type is "Identifier" ? "Property" : part.type,
            name: part.name,
            value,
            delim: part.delim,
            names: part.names,
            children: [
              isWhitespaceOrEmpty(part.children[0]) and part.children[0],
              part.name,
              isWhitespaceOrEmpty(part.children[2]) and part.children[2],
              part.children[3]?.token is ":" ? part.children[3] : ":",
              value,
              part.delim, // comma delimiter
            ]
          })
        }
      }
      let object = {
        type: "ObjectExpression",
        children: [
          glob.object.children.0, // {
          ...parts,
          glob.object.children.-1, // whitespace and }
        ],
        properties: parts,
        hoistDec,
      }
      if (refAssignment) {
        object = {
          type: "ParenthesizedExpression",
          children: ["(", ...refAssignment, object, ")"],
          expression: object,
        }
      }
      if (i is children.length - 1) return object
      return processCallMemberExpression({  // in case there are more
        ...node,
        children: [object, ...children.slice(i + 1)]
      })
    } else if (glob?.type is "PropertyBind") {
      // TODO: add ref to ensure object base evaluated only once
      const prefix = children.slice(0, i)
      return processCallMemberExpression({  // in case there are more
        ...node,
        children: [
          prefix,
          {
            ...glob,
            type: "PropertyAccess",
            children: [
              ...glob.children,
              ".bind(",
              prefix,
              ...glob.args.length > 0 ? [", "] : [],
              ...glob.args,
              ")",
            ]
          },
          ...children.slice(i + 1)
        ]
      })
    }
  }
  return node

/**
 * Replace this node with another, by modifying its parent's children.
 */
function replaceNode(node: ASTNodeBase, newNode: ASTNode): void
  unless node.parent?
    throw new Error "replaceNode failed: node has no parent"
  function recurse(children: ASTNode[]): boolean
    for each child, i of children
      if child is node
        children[i] = newNode
        return true
      else if Array.isArray child
        return true if recurse child
    return false
  unless recurse node.parent.children
    throw new Error "replaceNode failed: didn't find child node in parent"
  if newNode <? "object" and not Array.isArray newNode
    newNode.parent = node.parent

// Wrap expression in parentheses to make into a statement when:
// * object literal expression
// * anonymous function expression
// * comma operators applied to above
function makeExpressionStatement(expression: ASTNode): ASTNode
  if Array.isArray(expression) and expression[1]?[0]?[0]?[1]?.token is "," // CommaExpression
    [
      makeExpressionStatement expression[0]
      expression[1].map ([comma, exp]) => // CommaDelimiter AssignmentExpression
        [comma, makeExpressionStatement exp]
    ]
  else if expression?.type is "ObjectExpression" or
          (expression?.type is "FunctionExpression" and not expression.id)
    makeLeftHandSideExpression expression
  else
    expression

// Look for last property access like `.foo` or `[computed]` or root Identifier,
// before any calls like `(args)`, non-null assertions `!`, and optionals `?`.
// The return value should have a `name` property (for "Identifier" and
// "Index"), or have `type` of "Index" (for `[computed]`), or be undefined.
function lastAccessInCallExpression(exp) {
  return exp if exp.type is "Identifier"
  let children, i
  do {
    ({ children } = exp)
    i = children.length - 1
    while (i >= 0 and (
      children[i].type is "Call" ||
      children[i].type is "NonNullAssertion" ||
      children[i].type is "Optional"
    )) i--
    if (i < 0) return
    // Recurse into nested MemberExpression, e.g. from `x.y()`
  } while (children[i].type is "MemberExpression" and (exp = children[i]))
  return children[i]
}

// Given a MethodDefinition, convert into a FunctionExpression.
// Returns undefined if the method is a getter or setter.
function convertMethodToFunction(method) {
  const { signature, block } = method
  let { modifier, optional } = signature
  if (optional) return
  if (modifier) {
    if (modifier.get or modifier.set) {
      return
    } else if (modifier.async) {
      // put function after async
      modifier = [modifier.children[0][0], " function ", ...modifier.children.slice(1)]
    } else {
      modifier = ["function ", ...(modifier.children or [])]
    }
  } else {
    modifier = "function ";
  }
  return {
    ...signature,
    id: signature.name,
    signature,
    type: "FunctionExpression",
    children: [
      [modifier, ...signature.children.slice(1)],
      block,
    ],
    block,
  }
}

// Convert an ObjectExpression (with `properties`)
// into a set of JSX attributes.
// {foo} is equivalent to foo={foo}, and
// {foo, bar: baz} is equivalent to foo={foo} and bar={baz}.
// {...foo} is a special case.
function convertObjectToJSXAttributes(obj) {
  const { properties } = obj
  const parts = [] // JSX attributes
  const rest = []  // parts that need to be in {...rest} form
  for (let i = 0; i < properties.length; i++) {
    if (i > 0) parts.push(' ')
    const part = properties[i]
    switch (part.type) {
      case 'Identifier':
        parts.push([part.name, '={', part.name, '}'])
        break
      case 'Property':
        if (part.name.type is 'ComputedPropertyName') {
          rest.push(part)
        } else {
          parts.push([part.name, '={', insertTrimmingSpace(part.value, ''), '}'])
        }
        break
      case 'SpreadProperty':
        parts.push(['{', part.dots, part.value, '}'])
        break
      case 'MethodDefinition':
        const func = convertMethodToFunction(part)
        if (func) {
          parts.push([part.name, '={', convertMethodToFunction(part), '}'])
        } else {
          rest.push(part)
        }
        break
      default:
        throw new Error(`invalid object literal type in JSX attribute: ${part.type}`)
    }
  }
  if (rest.length) {
    parts.push(['{...{', ...rest, '}}'])
  }
  return parts
}

/**
 * Returns a new MethodDefinition node.
 */
function makeGetterMethod(name, ws, value, returnType, block?: BlockStatement, kind: { token: "get" | "set" } = { token: "get" }, autoReturn: boolean = true): MethodDefinition
  { token } := kind
  ws = insertTrimmingSpace(ws, "")
  let setVal
  parameters := token is "get" ?
    type: "Parameters"
    children: ["()"]
    names: []
    implicit: true
  :
    type: "Parameters"
    children: ["(", setVal = makeRef("value"), ")"]
    names: []
    implicit: false

  let expressions: StatementTuple[]
  if block
    // Duplicate block to avoid mutating original
    block = duplicateBlock(block)
    expressions = block.expressions
  else
    expressions = []
    block = {
      type: "BlockStatement"
      expressions
      children: ["{ ", expressions, " }"]
    }

  if autoReturn
    finalStatement: StatementTuple := token is "get" ?
      [ [expressions[0]?.[0] or "", ws], wrapWithReturn(value) ]
    :
      [ [expressions[0]?.[0] or "", ws], [ value, " = ", setVal ] ]

    expressions.push finalStatement

  children := [kind, " ", name, parameters, returnType, block]

  return {
    type: "MethodDefinition",
    children,
    name,
    signature: {
      type: "MethodSignature"
      modifier: {
        get: token is "get"
        set: token is "set"
        async: false
      },
      name,
      returnType,
    },
    block,
    parameters,
  }

function processBindingPatternLHS(lhs, tail): void
  // Expand AtBindings first before gathering splices
  adjustAtBindings(lhs, true)
  const [splices, thisAssignments] = gatherBindingCode(lhs)
  // TODO: This isn't quite right for compound assignments, may need to wrap with parens and use comma to return the complete value
  tail.push(...splices.map((s) => [", ", s]), ...thisAssignments.map((a) => [", ", a]))

function processAssignments(statements): void {
  // Move assignments/updates within LHS of assignments/updates
  // to run earlier via comma operator
  gatherRecursiveAll(statements, (n) => n.type is "AssignmentExpression" or n.type is "UpdateExpression")
    .forEach((exp) => {
      function extractAssignment(lhs) {
        let expr = lhs
        while expr.type is "ParenthesizedExpression"
          expr = expr.expression
        if (expr.type is "AssignmentExpression" ||
          expr.type is "UpdateExpression") {
          if (expr.type is "UpdateExpression" &&
            expr.children[0] is expr.assigned) {  // postfix update
            pre.push("(")
            post.push([", ", lhs, ")"])
          } else {
            pre.push(["(", lhs, ", "])
            post.push(")")
          }
          // TODO: use ref to avoid duplicating function calls
          return expr.assigned
        }
      }
      const pre = [], post = []
      switch (exp.type) {
        case "AssignmentExpression":
          if (!exp.lhs) return
          exp.lhs.forEach((lhsPart, i) => {
            let newLhs = extractAssignment(lhsPart[1])
            if (newLhs) {
              lhsPart[1] = newLhs
            }
          })
          break
        case "UpdateExpression":
          let newLhs = extractAssignment(exp.assigned)
          if (newLhs) {
            const i = exp.children.indexOf(exp.assigned)
            exp.assigned = exp.children[i] = newLhs
          }
          break
      }
      if (pre.length) exp.children.unshift(...pre)
      if (post.length) exp.children.push(...post)
      // TODO: need to make this a parenthesized expression when when we add parens
    })

  gatherRecursiveAll(statements, (n) => n.type is "AssignmentExpression" and n.names is null)
    .forEach((exp) => {
      let { lhs: $1, exp: $2 } = exp, tail = [], i = 0, len = $1.length

      // identifier=, xor=, ++=
      if $1.some((left) => left[left.length - 1].special)
        if ($1.length !== 1) throw new Error("Only one assignment with id= is allowed")
        [, lhs, , op] := $1[0]
        { call, omitLhs } := op
        // Wrap right-hand side with call
        index := exp.children.indexOf($2)
        if (index < 0) throw new Error("Assertion error: exp not in AssignmentExpression")
        exp.children.splice index, 1,
          exp.exp = $2 = [call, "(", lhs, ", ", $2, ")"]
        if omitLhs
          replaceNode exp, $2

      // Force parens around destructuring object assignments
      // Walk from left to right the minimal number of parens are added and enclose all destructured assignments
      // TODO: Could validate some lhs ecmascript rules here if we wanted to
      let wrapped = false
      while (i < len) {
        const lastAssignment = $1[i++]
        const [, lhs, , op] = lastAssignment
        if (op.token !== "=") continue

        if (lhs.type is "ObjectExpression" or lhs.type is "ObjectBindingPattern") {
          // Wrap with parens to distinguish from braced blocks
          if (!wrapped) {
            wrapped = true
            lhs.children.splice(0, 0, "(")
            tail.push(")")
          }
        }
      }

      // TODO: Handle optional assignment refs

      // Walk from right to left to handle splices
      i = len - 1
      while (i >= 0) {
        const lastAssignment = $1[i]

        if (lastAssignment[3].token is "=") {
          const lhs = lastAssignment[1]

          // Splice assignment
          if (lhs.type is "MemberExpression") {
            const members = lhs.children
            const lastMember = members[members.length - 1]

            // TODO: this is kind of bonkers
            if (lastMember.type is "SliceExpression") {
              const { start, end, children: c } = lastMember
              // TODO: don't lose as many source mappings
              c[0].token = ".splice("
              c[1] = start
              c[2] = ", "
              if (end)
                c[3] = [end, " - ", start]
              else
                c[3] = ["1/0"]
              c[4] = [", ...", $2]
              c[5] = ")"

              // Remove assignment token
              lastAssignment.pop()
              if (isWhitespaceOrEmpty(lastAssignment[2])) lastAssignment.pop()
              // TODO: this only works for the last assignment, not multiple splice assignments, or splice assignments earlier in the chain
              if ($1.length > 1) {
                throw new Error("Not implemented yet! TODO: Handle multiple splice assignments")
              }

              exp.children = [$1]
              exp.names = []
              return
            }
          } else if (lhs.type is "ObjectBindingPattern" or lhs.type is "ArrayBindingPattern") {
            processBindingPatternLHS(lhs, tail)
          }
          // NOTE: currently not processing any non-binding pattern ObjectExpression or ArrayExpressions
          // This might not be correct in all situations, esp BindingPatterns nested inside ObjectExpressions
        }
        i--
      }

      // Gather all identifier names from the lhs array
      exp.names = $1.flatMap(([, l]) => l.names or [])
      const index = exp.children.indexOf($2)
      if (index < 0) throw new Error("Assertion error: exp not in AssignmentExpression")
      exp.children.splice(index + 1, 0, ...tail)
    })
}

function attachPostfixStatementAsExpression(exp, post: [WSNode, IfStatement | IterationStatement | DoStatement | ForStatement])
  postfixStatement := post[1]

  switch postfixStatement.type
    case "ForStatement":
    case "IterationStatement":
    case "DoStatement": {
      statement := addPostfixStatement(exp, ...post)
      return {
        type: "IterationExpression",
        children: [statement],
        block: statement.block,
        statement,
      }
    }
    case "IfStatement":
      return expressionizeIfStatement { ...postfixStatement, then: exp }
    default:
      throw new Error("Unknown postfix statement")

function processTypes(node: ASTNode)
  // T? -> T | undefined; T?? -> T | undefined | null
  gatherRecursiveAll node, (n) => n.type is "UnaryType"
  // @ts-ignore
  .forEach (unary: ASTNodeBase): void =>
    let last: ASTNode
    count .= 0
    while unary.suffix.length and unary.suffix.-1?.token is "?"
      last = unary.suffix.pop()
      count++
    return unless count
    if unary.parent?.type is "TypeTuple"
      // Leave one ? inside a type tuple
      if count is 1
        unary.suffix.push last
        return
      replaceNode unary, [
        getTrimmingSpace unary
        "("
        parenthesizeType insertTrimmingSpace unary, ""
        " | null)"
        last
      ]
    else
      replaceNode unary, [
        getTrimmingSpace unary
        "("
        parenthesizeType insertTrimmingSpace unary, ""
        count is 1 ? " | undefined" : " | undefined | null"
        ")"
      ]

/**
Wrap any remaining statement expressions in IIFE.
*/
function processStatementExpressions(statements: StatementTuple[]): void
  gatherRecursiveAll(statements, .type is "StatementExpression")
    .forEach (_exp) =>
      exp := _exp as! StatementExpression
      { statement } := exp
      let ws
      unless exp.children[0] is exp.statement
        ws = exp.children[0]

      switch statement.type
        when "IfStatement"
          // TODO: detect non-expressionable ifs and wrap in iife
          if expression := expressionizeIfStatement(statement)
            exp.statement = expression
            exp.children = [exp.statement]
          else
            exp.children = wrapIIFE([["", statement]])
        when "IterationExpression"
          // Do nothing, handled separately currently
        else
          exp.children = wrapIIFE([["", statement]])

      exp.children.unshift(ws) if ws

function processProgram(root: BlockStatement, config, m, ReservedWord: ParseRule): void {
  // invariants
  assert.equal(m.forbidBracedApplication.length, 1, "forbidBracedApplication")
  assert.equal(m.forbidClassImplicitCall.length, 1, "forbidClassImplicitCall")
  assert.equal(m.forbidIndentedApplication.length, 1, "forbidIndentedApplication")
  assert.equal(m.forbidNewlineBinaryOp.length, 1, "forbidNewlineBinaryOp")
  assert.equal(m.forbidTrailingMemberProperty.length, 1, "forbidTrailingMemberProperty")
  assert.equal(m.JSXTagStack.length, 1, "JSXTagStack")

  addParentPointers(root)

  const { expressions: statements } = root

  processTypes(statements)
  processDeclarationConditions(statements)
  processPipelineExpressions(statements)
  processDeclarations(statements)
  processAssignments(statements)
  processStatementExpressions(statements)
  processPatternMatching(statements, ReservedWord)

  // Modify iteration expressions
  gatherRecursiveAll(statements, (n) => n.type is "IterationExpression")
    .forEach((e) => expressionizeIteration(e))

  // Hoist hoistDec attributes to actual declarations.
  // NOTE: This should come after iteration expressions get processed
  // into IIFEs.
  hoistRefDecs(statements)

  // Adding implicit returns should happen after hoisting any ref declarations
  // so their target node can be found in the block without being inside a return
  processFunctions(statements, config)

  // Insert prelude
  statements.unshift(...m.prelude)

  if (config.autoLet) {
    createConstLetDecs(statements, [], "let")
  } else if(config.autoConst) {
    createConstLetDecs(statements, [], "const")
  } else if (config.autoVar) {
    createVarDecs(statements, [])
  }

  processBlocks(statements)

  populateRefs(statements)
  adjustAtBindings(statements)
}

function populateRefs(statements: ASTNode): void {
  const refNodes = gatherRecursive(statements, ({ type }) => type is "Ref")

  if (refNodes.length) {
    // Find all ids within nested scopes
    const ids = gatherRecursive(statements, (s) => s.type is "Identifier")
    const names = new Set(ids.flatMap(({ names }) => names or []))

    // Populate each ref
    refNodes.forEach((ref) => {
      const { type, base } = ref
      if (type !== "Ref") return

      ref.type = "Identifier"

      let n = 0
      let name = base

      // check for name collisions and increment name suffix
      while (names.has(name)) {
        n++
        name = `${base}${n}`
      }

      names.add(name)
      ref.children = ref.names = [name]
    })
  }
}

function reorderBindingRestProperty(props) {
  const names = props.flatMap((p) => p.names)

  let restIndex = -1
  let restCount = 0
  props.forEach(({ type }, i) => {
    if (type is "BindingRestProperty") {
      if (restIndex < 0) restIndex = i
      restCount++
    }
  })

  if (restCount is 0) {
    return {
      children: props,
      names,
    }
  } else if (restCount is 1) {
    let after = props.slice(restIndex + 1)
    let rest = props[restIndex]

    props = props.slice(0, restIndex);

    // Swap delimiters of last property and rest so that an omitted trailing comma doesn't end up in the middle
    if (after.length) {
      const {delim: restDelim} = rest,
        lastAfterProp = after[after.length - 1],
        {delim: lastDelim, children: lastAfterChildren} = lastAfterProp

      rest = {
        ...rest,
        delim: lastDelim,
        children: [...rest.children.slice(0, -1), lastDelim],
      }
      after = [
        ...after.slice(0, -1),
        {
          ...lastAfterProp,
          delim: restDelim,
          children: [...lastAfterChildren.slice(0, -1), restDelim]
        }
      ]
    }

    // JS forbids trailing comma after rest property
    if Array.isArray(rest.delim) and rest.delim.-1?.token is ","
      // Can't mutate delim in case of cached nodes
      rest.delim = rest.delim.slice(0, -1)
      rest.children = [ ...rest.children.slice(0, -1), rest.delim ]

    const children = [...props, ...after, rest]

    return {
      children,
      names,
    }
  }

  return {
    children: [{
      type: "Error",
      message: "Multiple rest properties in object pattern",
    }, props]
  }
}

/**
 * Replace all nodes that match predicate with replacer(node)
 */
function replaceNodes(root, predicate, replacer)
  return root unless root?
  array := Array.isArray(root) ? root : root.children
  unless array
    if predicate root
      return replacer root, root
    else
      return root
  for each node, i of array
    return unless node?
    if predicate node
      array[i] = replacer node, root
    else
      replaceNodes node, predicate, replacer
  return root

function typeOfJSX(node, config, getRef) {
  switch (node.type) {
    case "JSXElement":
      return typeOfJSXElement(node, config, getRef)
    case "JSXFragment":
      return typeOfJSXFragment(node, config, getRef)
  }
}

function typeOfJSXElement(node, config, getRef) {
  if (config.solid) {
    if (config.server and !config.client) {  // server only
      return ["string"]
    }
    let { tag } = node
    // "An intrinsic element always begins with a lowercase letter,
    // and a value-based element always begins with an uppercase letter."
    // [https://www.typescriptlang.org/docs/handbook/jsx.html]
    const clientType =
      tag[0] is tag[0].toLowerCase() ?
        [getRef("IntrinsicElements"), '<"', tag, '">'] :
        ['ReturnType<typeof ', tag, '>']
    if (config.server) {  // isomorphic code for client + server
      return ["string", " | ", clientType]
    } else {  // client only (default)
      return clientType
    }
  }
}

function typeOfJSXFragment(node, config, getRef) {
  if (config.solid) {
    let type = []
    let lastType
    for (let child of node.jsxChildren) {
      switch (child.type) {
        case "JSXText":
          // Solid combines multiple consecutive texts into one string
          if (lastType !== "JSXText") {
            type.push("string")
          }
          break
        case "JSXElement":
          type.push(typeOfJSXElement(child, config, getRef))
          break
        case "JSXFragment":
          // Solid flattens fragments of fragments into one array.
          type.push(...typeOfJSXFragment(child, config, getRef))
          break
        case "JSXChildExpression":
          // Solid discards empty expressions
          if (child.expression) {
            type.push(["typeof ", child.expression])
          }
          break
        default:
          throw new Error(`unknown child in JSXFragment: ${JSON.stringify(child)}`)
      }
      lastType = child.type
    }
    // Solid doesn't wrap single fragment child in an array
    if (type.length is 1) {
      return type[0]
    } else {
      type = type.flatMap((t) => [t, ", "])
      type.pop() // remove trailing comma
      return ["[", type, "]"]
    }
  }
}

export {
  addPostfixStatement
  adjustBindingElements
  attachPostfixStatementAsExpression
  blockWithPrefix
  convertObjectToJSXAttributes
  dedentBlockString
  dedentBlockSubstitutions
  deepCopy
  expressionizeTypeIf
  forRange
  gatherBindingCode
  gatherRecursive
  getIndentLevel
  getPrecedence
  getTrimmingSpace
  hasAwait
  hasYield
  insertTrimmingSpace
  isEmptyBareBlock
  isWhitespaceOrEmpty
  lastAccessInCallExpression
  literalValue
  makeAmpersandFunction
  makeEmptyBlock
  makeExpressionStatement
  makeGetterMethod
  makeLeftHandSideExpression
  makeRef
  maybeRef
  modifyString
  negateCondition
  precedenceStep
  processAssignmentDeclaration
  processBinaryOpExpression
  processCallMemberExpression
  processCoffeeInterpolation
  processForInOf
  processProgram
  processUnaryExpression
  quoteString
  reorderBindingRestProperty
  replaceNodes
  skipImplicitArguments
  typeOfJSX
  wrapIIFE
}

DanielXMoore / Civet / 8127312101

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