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refactor: make functions non-semantic types

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Merge request lab2425_spring/WACC_37!13
This commit is contained in:
Gleb Koval 2025-02-07 14:12:58 +00:00
commit c547a2a37f
5 changed files with 90 additions and 92 deletions
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12
src/main/wacc/Error.scala
View File

@ -5,7 +5,9 @@ import wacc.types._
enum Error {
case DuplicateDeclaration(ident: ast.Ident)
case UndefinedIdentifier(ident: ast.Ident, identType: renamer.IdentType)
case UndeclaredVariable(ident: ast.Ident)
case UndefinedFunction(ident: ast.Ident)
case FunctionParamsMismatch(pos: Position, expected: Int, got: Int)
case SemanticError(pos: Position, msg: String)
case TypeMismatch(pos: Position, expected: SemType, got: SemType, msg: String)
@ -19,9 +21,13 @@ def printError(error: Error)(using errorContent: String): Unit = {
printPosition(ident.pos)
println(s"Duplicate declaration of identifier ${ident.v}")
highlight(ident.pos, ident.v.length)
case Error.UndefinedIdentifier(ident, identType) =>
case Error.UndeclaredVariable(ident) =>
printPosition(ident.pos)
println(s"Undefined ${identType.toString.toLowerCase()} ${ident.v}")
println(s"Undeclared variable ${ident.v}")
highlight(ident.pos, ident.v.length)
case Error.UndefinedFunction(ident) =>
printPosition(ident.pos)
println(s"Undefined function ${ident.v}")
highlight(ident.pos, ident.v.length)
case Error.FunctionParamsMismatch(pos, expected, got) =>
printPosition(pos)

4
src/main/wacc/Main.scala
View File

@ -34,8 +34,8 @@ def compile(contents: String): Int = {
parser.parse(contents) match {
case Success(prog) =>
given errors: mutable.Builder[Error, List[Error]] = List.newBuilder
val names = renamer.rename(prog)
given ctx: typeChecker.TypeCheckerCtx = typeChecker.TypeCheckerCtx(names, errors)
val (names, funcs) = renamer.rename(prog)
given ctx: typeChecker.TypeCheckerCtx = typeChecker.TypeCheckerCtx(names, funcs, errors)
typeChecker.check(prog)
if (errors.result.nonEmpty) {
given errorContent: String = contents

106
src/main/wacc/renamer.scala
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@ -6,14 +6,14 @@ object renamer {
import ast._
import types._
enum IdentType {
private enum IdentType {
case Func
case Var
}
private case class Scope(
current: mutable.Map[(String, IdentType), Ident],
parent: Map[(String, IdentType), Ident]
private class Scope(
val current: mutable.Map[(String, IdentType), Ident],
val parent: Map[(String, IdentType), Ident]
) {
/** Create a new scope with the current scope as its parent.
@ -27,12 +27,10 @@ object renamer {
/** Attempt to add a new identifier to the current scope. If the identifier already exists in
* the current scope, add an error to the error list.
*
* @param semType
* The semantic type of the identifier.
* @param ty
* The semantic type of the variable identifier, or function identifier type.
* @param name
* The name of the identifier.
* @param identType
* The identifier type (function or variable).
* @param globalNames
* The global map of identifiers to semantic types - the identifier will be added to this
* map.
@ -42,22 +40,46 @@ object renamer {
* @param errors
* The list of errors to append to.
*/
def add(semType: SemType, name: Ident, identType: IdentType)(using
def add(ty: SemType | FuncType, name: Ident)(using
globalNames: mutable.Map[Ident, SemType],
globalFuncs: mutable.Map[Ident, FuncType],
globalNumbering: mutable.Map[String, Int],
errors: mutable.Builder[Error, List[Error]]
) = {
if (current.contains((name.v, identType))) {
val identType = ty match {
case _: SemType => IdentType.Var
case _: FuncType => IdentType.Func
}
current.get((name.v, identType)) match {
case Some(Ident(_, uid)) =>
errors += Error.DuplicateDeclaration(name)
} else {
name.uid = uid
case None =>
val uid = globalNumbering.getOrElse(name.v, 0)
name.uid = uid
current((name.v, identType)) = name
ty match {
case semType: SemType =>
globalNames(name) = semType
case funcType: FuncType =>
globalFuncs(name) = funcType
}
globalNumbering(name.v) = uid + 1
}
}
private def get(name: String, identType: IdentType): Option[Ident] =
// Unfortunately map defaults only work with `.apply()`, which throws an error when the key is not found.
// Neither is there a way to check whether a default exists, so we have to use a try-catch.
try {
Some(current.withDefault(parent)((name, identType)))
} catch {
case _: NoSuchElementException => None
}
def getVar(name: String): Option[Ident] = get(name, IdentType.Var)
def getFunc(name: String): Option[Ident] = get(name, IdentType.Func)
}
/** Check scoping of all variables and functions in the program. Also generate semantic types for
@ -72,8 +94,9 @@ object renamer {
*/
def rename(prog: Program)(using
errors: mutable.Builder[Error, List[Error]]
): Map[Ident, SemType] =
): (Map[Ident, SemType], Map[Ident, FuncType]) = {
given globalNames: mutable.Map[Ident, SemType] = mutable.Map.empty
given globalFuncs: mutable.Map[Ident, FuncType] = mutable.Map.empty
given globalNumbering: mutable.Map[String, Int] = mutable.Map.empty
val scope = Scope(mutable.Map.empty, Map.empty)
val Program(funcs, main) = prog
@ -84,7 +107,7 @@ object renamer {
val paramType = SemType(param.paramType)
paramType
}
scope.add(KnownType.Func(SemType(retType), paramTypes), name, IdentType.Func)
scope.add(FuncType(SemType(retType), paramTypes), name)
(params zip paramTypes, body)
}
// Only then rename the function bodies
@ -92,12 +115,13 @@ object renamer {
.foreach { case (params, body) =>
val functionScope = scope.subscope
params.foreach { case (param, paramType) =>
functionScope.add(paramType, param.name, IdentType.Var)
functionScope.add(paramType, param.name)
}
body.toList.foreach(rename(functionScope.subscope)) // body can shadow function params
}
main.toList.foreach(rename(scope))
globalNames.toMap
(globalNames.toMap, globalFuncs.toMap)
}
/** Check scoping of all identifies in a given AST node.
*
@ -117,6 +141,7 @@ object renamer {
node: Ident | Stmt | LValue | RValue | Expr
)(using
globalNames: mutable.Map[Ident, SemType],
globalFuncs: mutable.Map[Ident, FuncType],
globalNumbering: mutable.Map[String, Int],
errors: mutable.Builder[Error, List[Error]]
): Unit = node match {
@ -126,7 +151,7 @@ object renamer {
// Order matters here. Variable isn't declared until after the value is evaluated.
rename(scope)(value)
// Attempt to add the new variable to the current scope.
scope.add(SemType(synType), name, IdentType.Var)
scope.add(SemType(synType), name)
}
case If(cond, thenStmt, elseStmt) => {
rename(scope)(cond)
@ -158,7 +183,12 @@ object renamer {
rename(scope)(snd)
}
case Call(name, args) => {
renameIdent(scope, name, IdentType.Func)
scope.getFunc(name.v) match {
case Some(Ident(_, uid)) => name.uid = uid
case None =>
errors += Error.UndefinedFunction(name)
scope.add(FuncType(?, args.map(_ => ?)), name)
}
args.foreach(rename(scope))
}
case Fst(elem) => rename(scope)(elem)
@ -175,41 +205,15 @@ object renamer {
rename(scope)(op.y)
}
// Default to variables. Only `call` uses IdentType.Func.
case id: Ident => renameIdent(scope, id, IdentType.Var)
case id: Ident => {
scope.getVar(id.v) match {
case Some(Ident(_, uid)) => id.uid = uid
case None =>
errors += Error.UndeclaredVariable(id)
scope.add(?, id)
}
}
// These literals cannot contain identifies, exit immediately.
case IntLiter(_) | BoolLiter(_) | CharLiter(_) | StrLiter(_) | PairLiter() | Skip() => ()
}
/** Lookup an identifier in the current scope and rename it. If the identifier is not found, add
* an error to the error list and add it to the current scope with an unknown type.
*
* @param scope
* The current scope and flattened parent scope.
* @param ident
* The identifier to rename.
* @param identType
* The type of the identifier (function or variable).
* @param globalNames
* Used to add not-found identifiers to scope.
* @param globalNumbering
* Used to add not-found identifiers to scope.
* @param errors
* The list of errors to append to.
*/
private def renameIdent(scope: Scope, ident: Ident, identType: IdentType)(using
globalNames: mutable.Map[Ident, SemType],
globalNumbering: mutable.Map[String, Int],
errors: mutable.Builder[Error, List[Error]]
): Unit = {
// Unfortunately map defaults only work with `.apply()`, which throws an error when the key is not found.
// Neither is there a way to check whether a default exists, so we have to use a try-catch.
try {
val Ident(_, uid) = scope.current.withDefault(scope.parent)((ident.v, identType))
ident.uid = uid
} catch {
case _: NoSuchElementException =>
errors += Error.UndefinedIdentifier(ident, identType)
scope.add(?, ident, identType)
}
}
}

26
src/main/wacc/typeChecker.scala
View File

@ -9,9 +9,12 @@ object typeChecker {
case class TypeCheckerCtx(
globalNames: Map[Ident, SemType],
globalFuncs: Map[Ident, FuncType],
errors: mutable.Builder[Error, List[Error]]
) {
def typeOf(ident: Ident): SemType = globalNames.withDefault { case Ident(_, -1) => ? }(ident)
def typeOf(ident: Ident): SemType = globalNames(ident)
def funcType(ident: Ident): FuncType = globalFuncs(ident)
def error(err: Error): SemType =
errors += err
@ -23,7 +26,6 @@ object typeChecker {
case Is(ty: SemType, msg: String)
case IsSymmetricCompatible(ty: SemType, msg: String)
case IsUnweakanable(ty: SemType, msg: String)
case IsVar(msg: String)
case IsEither(ty1: SemType, ty2: SemType, msg: String)
case Never(msg: String)
}
@ -42,9 +44,6 @@ object typeChecker {
ty.satisfies(Constraint.Is(ty2, msg), pos)
case (ty, Constraint.Is(ty2, msg)) => ty.satisfies(Constraint.IsUnweakanable(ty2, msg), pos)
case (ty, Constraint.Unconstrained) => ty
case (KnownType.Func(_, _), Constraint.IsVar(msg)) =>
ctx.error(Error.SemanticError(pos, msg))
case (ty, Constraint.IsVar(msg)) => ty
case (ty, Constraint.Never(msg)) =>
ctx.error(Error.SemanticError(pos, msg))
case (ty, Constraint.IsEither(ty1, ty2, msg)) =>
@ -74,13 +73,10 @@ object typeChecker {
ctx: TypeCheckerCtx
): Unit = {
prog.funcs.foreach { case FuncDecl(_, name, _, stmts) =>
ctx.typeOf(name) match {
case KnownType.Func(retType, _) =>
val FuncType(retType, _) = ctx.funcType(name)
stmts.toList.foreach(
checkStmt(_, Constraint.Is(retType, s"function ${name.v} must return $retType"))
)
case _ => ctx.error(Error.InternalError(name.pos, "function declaration with non-function"))
}
}
prog.main.toList.foreach(checkStmt(_, Constraint.Never("main function must not return")))
}
@ -138,7 +134,7 @@ object typeChecker {
checkValue(expr, Constraint.Is(KnownType.Int, "exit value must be int"))
case Print(expr, _) =>
// This constraint should never fail, the scope-checker should have caught it already
checkValue(expr, Constraint.IsVar("print value must be a variable"))
checkValue(expr, Constraint.Unconstrained)
case If(cond, thenStmt, elseStmt) =>
checkValue(cond, Constraint.Is(KnownType.Bool, "if condition must be a bool"))
thenStmt.toList.foreach(checkStmt(_, returnConstraint))
@ -192,9 +188,7 @@ object typeChecker {
)
.satisfies(constraint, l.pos)
case Call(id, args) =>
val funcTy = ctx.typeOf(id)
funcTy match {
case KnownType.Func(retTy, paramTys) =>
val FuncType(retTy, paramTys) = ctx.funcType(id)
if (args.length != paramTys.length) {
ctx.error(Error.FunctionParamsMismatch(id.pos, paramTys.length, args.length))
}
@ -202,10 +196,6 @@ object typeChecker {
checkValue(arg, Constraint.Is(paramTy, s"argument type mismatch in function ${id.v}"))
}
retTy.satisfies(constraint, id.pos)
// Should never happen, the scope-checker should have caught this already
// ctx error had it not
case _ => ctx.error(Error.InternalError(id.pos, "function call to non-function"))
}
case Fst(elem) =>
checkValue(
elem,
@ -213,7 +203,6 @@ object typeChecker {
) match {
case what @ KnownType.Pair(left, _) =>
left.satisfies(constraint, elem.pos)
case ? => ?.satisfies(constraint, elem.pos)
case _ => ctx.error(Error.InternalError(elem.pos, "fst must be applied to a pair"))
} // satisfies constraint
case Snd(elem) =>
@ -222,7 +211,6 @@ object typeChecker {
Constraint.Is(KnownType.Pair(?, ?), "snd must be applied to a pair")
) match {
case KnownType.Pair(_, right) => right.satisfies(constraint, elem.pos)
case ? => ?.satisfies(constraint, elem.pos)
case _ => ctx.error(Error.InternalError(elem.pos, "snd must be applied to a pair"))
}

4
src/main/wacc/types.scala
View File

@ -11,7 +11,6 @@ object types {
case KnownType.String => "string"
case KnownType.Array(elem) => s"$elem[]"
case KnownType.Pair(left, right) => s"pair($left, $right)"
case KnownType.Func(ret, params) => s"function returning $ret with params $params"
case ? => "?"
}
}
@ -24,7 +23,6 @@ object types {
case String
case Array(elem: SemType)
case Pair(left: SemType, right: SemType)
case Func(ret: SemType, params: List[SemType])
}
object SemType {
@ -40,4 +38,6 @@ object types {
case UntypedPairType() => KnownType.Pair(?, ?)
}
}
case class FuncType(returnType: SemType, params: List[SemType])
}