package typechecker
import (
"strings"
"github.com/marzeq/quokka/parser"
"github.com/marzeq/quokka/shared"
)
type VarSig struct {
Type shared.Type
Mutable bool
}
type FunctionSigArg struct {
Name string
Type shared.Type
Mutable bool
}
type FunctionSig struct {
Name string
ArgTypes []FunctionSigArg
HasVariadic bool
RetType shared.Type
ImplicitReturn bool
}
type (
VarTable = *shared.SymbolTable[*VarSig]
FuncTable = *shared.SymbolTable[*FunctionSig]
TypeTable = shared.TypeTable
)
type TypeChecker struct {
VarTable VarTable
FuncTable FuncTable
TypeTable TypeTable
}
func NewTypeChecker() *TypeChecker {
return &TypeChecker{
VarTable: shared.NewSymbolTable[*VarSig](),
FuncTable: shared.NewSymbolTable[*FunctionSig](),
TypeTable: shared.NewTypeTable(),
}
}
func (tc *TypeChecker) TypeCheck(root *parser.RootNode) (*parser.RootNode, map[string]*FunctionSig, TypeTable, error) {
for _, n := range root.Body {
switch node := n.(type) {
case *parser.FunctionDefNode:
fsig, err := tc.ExtractFunctionSig(node)
if err != nil {
return nil, nil, nil, err
}
if ok := tc.FuncTable.Define(fsig.Name, fsig); !ok {
return nil, nil, nil, shared.NewError(node.Loc, "function '%s' is already defined", fsig.Name)
}
if fsig.Name == "main" && fsig.RetType != shared.PRIMITIVE_I32 {
return nil, nil, nil, shared.NewError(node.Loc, "'main' function must be of '%s' return type", shared.PRIMITIVE_I32)
}
case *parser.StructDefNode:
if _, ok := tc.TypeTable.Lookup(node.Name); ok {
return nil, nil, nil, shared.NewError(node.Loc, "struct '%s' is already defined", node.Name)
}
fields := make([]shared.Pair[string, shared.Type], len(node.Fields))
for i, field := range node.Fields {
tpe := field.R.Name
resolved, ok := tc.TypeTable.Lookup(tpe)
if !ok {
return nil, nil, nil, shared.NewError(field.R.Loc, "field '%s' has undefined type '%s'", field.L, tpe)
}
fields[i] = shared.Pair[string, shared.Type]{L: field.L, R: resolved}
}
tc.TypeTable.Define(node.Name, shared.Struct{
Fields: fields,
})
}
}
for _, n := range root.Body {
switch node := n.(type) {
case *parser.FunctionDefNode:
sig, _ := tc.FuncTable.Lookup(node.Name)
tc.enterScope()
if err := tc.typeCheckFunction(node, sig); err != nil {
return nil, nil, nil, err
}
tc.exitScope()
}
}
return root, tc.FuncTable.GetScope(), tc.TypeTable, nil
}
func (tc *TypeChecker) enterScope() {
tc.VarTable.EnterScope()
tc.FuncTable.EnterScope()
}
func (tc *TypeChecker) exitScope() {
tc.VarTable.ExitScope()
tc.FuncTable.ExitScope()
}
func (tc *TypeChecker) typeCheckFunction(funcNode *parser.FunctionDefNode, sig *FunctionSig) error {
for _, arg := range sig.ArgTypes {
tc.VarTable.Define(arg.Name, &VarSig{
Type: arg.Type,
Mutable: arg.Mutable,
})
}
if funcNode.Body == nil {
return nil
}
switch body := funcNode.Body.(type) {
case *parser.BlockNode:
_, err := tc.typeCheckBlock(body, sig, false, true)
return err
default:
if expr, ok := body.(parser.ExpressionNode); ok {
exprType, err := tc.typeCheckExpression(expr, sig.RetType)
if err != nil {
return err
}
if !shared.CanCoerceTo(exprType, sig.RetType) {
return shared.NewError(funcNode.RetType.Loc, "function '%s' expects return type '%s' but returns '%s'",
funcNode.Name, sig.RetType, exprType)
}
if expr.GetType() == shared.PRIMITIVE_UNTYPED_INT && sig.RetType != shared.PRIMITIVE_VOID {
SetNodeType(expr, sig.RetType)
}
return nil
}
return shared.NewError(body.GetLoc(), "function body must be a block or an expression")
}
}
func (tc *TypeChecker) typeCheckBlock(blockNode *parser.BlockNode, sig *FunctionSig, isLoop bool, isMainBody bool) (bool, error) {
foundReturn := false
for i, n := range blockNode.Body {
switch node := n.(type) {
case *parser.DeclarationNode:
varName, varSig, err := tc.typeCheckDeclaration(node)
if err != nil {
return false, err
}
if ok := tc.VarTable.Define(varName, varSig); !ok {
return false, shared.NewError(node.Loc, "variable '%s' is already declared in this scope", varName)
}
case *parser.FunctionDefNode:
fsig, err := tc.ExtractFunctionSig(node)
if err != nil {
return false, err
}
if ok := tc.FuncTable.Define(fsig.Name, fsig); !ok {
return false, shared.NewError(node.Loc, "function '%s' is already defined", fsig.Name)
}
if sig != nil { tc.enterScope() }
if err := tc.typeCheckFunction(node, fsig); err != nil {
return false, err
}
if sig != nil { tc.exitScope() }
case *parser.AssignmentNode:
if err := tc.typeCheckAssignment(node); err != nil {
return false, err
}
case *parser.FunctionCallNode:
if _, err := tc.typeCheckFunctionCall(node); err != nil {
return false, err
}
case *parser.ControlKeywordNode:
switch node.Keyword {
case parser.KEYWORD_TYPE_RETURN:
if sig == nil {
return false, shared.NewError(node.Loc, "cannot return from here")
}
var retType shared.Type = shared.PRIMITIVE_VOID
if node.ReturnValue != nil {
var err error
retType, err = tc.typeCheckExpression(node.ReturnValue, sig.RetType)
if err != nil {
return false, err
}
if !shared.CanCoerceTo(retType, sig.RetType) {
return false, shared.NewError(node.Loc, "wrong return type for function, expected '%s' got '%s'", sig.RetType, retType)
}
SetNodeType(node.ReturnValue, sig.RetType)
} else if sig.RetType != shared.PRIMITIVE_VOID {
return false, shared.NewError(node.Loc, "wrong return type for function, expected '%s' got void", sig.RetType)
}
foundReturn = true
if i != len(blockNode.Body)-1 {
return false, shared.NewError(blockNode.Body[i+1].GetLoc(), "dead code following return statement")
}
case parser.KEYWORD_TYPE_BREAK, parser.KEYWORD_TYPE_CONTINUE:
if !isLoop {
return false, shared.NewError(node.Loc, "'%s' statement outside a loop", node.Keyword)
}
}
case *parser.BlockNode:
if sig != nil { tc.enterScope() }
returns, err := tc.typeCheckBlock(node, sig, isLoop, false)
if err != nil {
return false, err
}
if sig != nil { tc.exitScope() }
if i == len(blockNode.Body)-1 && !foundReturn {
foundReturn = returns
}
case *parser.ForNode:
if err := tc.typeCheckForLoop(node, sig); err != nil {
return false, err
}
case *parser.IfNode:
if sig != nil { tc.enterScope() }
returns, err := tc.typeCheckIfStatement(node, sig, isLoop)
if err != nil {
return false, err
}
if sig != nil { tc.exitScope() }
if i == len(blockNode.Body)-1 && !foundReturn {
foundReturn = returns
}
default:
return false, shared.NewError(node.GetLoc(), "unexpected node in block when type checking")
}
}
if isMainBody {
if !foundReturn && sig.RetType != shared.PRIMITIVE_VOID {
return false, shared.NewError(blockNode.Loc, "function with return type '%s' is missing a return statement", sig.RetType)
}
sig.ImplicitReturn = !foundReturn
}
return foundReturn, nil
}
func (tc *TypeChecker) typeCheckExpression(en parser.ExpressionNode, expectedType shared.Type) (shared.Type, error) {
switch exprNode := en.(type) {
case *parser.IdentifierNode:
varSig, ok := tc.VarTable.Lookup(exprNode.Name)
if !ok {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "undefined variable '%s'", exprNode.Name)
}
gotType, err := ResolveFieldChain(exprNode, varSig.Type)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
return gotType, nil
case *parser.NumberLiteralNode:
exprType := shared.PRIMITIVE_UNTYPED_INT
if expectedType != shared.PRIMITIVE_VOID && shared.CanCoerceTo(exprType, expectedType) {
exprNode.ExprType = expectedType
return expectedType, nil
}
exprNode.ExprType = exprType
return exprType, nil
case *parser.CharLiteralNode:
exprNode.ExprType = shared.PRIMITIVE_CHAR
return shared.PRIMITIVE_CHAR, nil
case *parser.StringLiteralNode:
exprNode.ExprType = shared.PRIMITIVE_CSTRING
return shared.PRIMITIVE_CSTRING, nil
case *parser.BoolLiteralNode:
exprNode.ExprType = shared.PRIMITIVE_BOOL
return shared.PRIMITIVE_BOOL, nil
case *parser.FunctionCallNode:
return tc.typeCheckFunctionCall(exprNode)
case *parser.UnaryOpNode:
operandType, err := tc.typeCheckExpression(exprNode.Operand, shared.PRIMITIVE_VOID)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
if expectedType != shared.PRIMITIVE_VOID && operandType == shared.PRIMITIVE_UNTYPED_INT && shared.IsNumericType(expectedType) {
SetNodeType(exprNode.Operand, expectedType)
operandType = expectedType
}
switch exprNode.Op {
case parser.UNARY_OP_LOGICAL_NOT:
if operandType != shared.PRIMITIVE_BOOL {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Operand.GetLoc(), "unary operator 'not' expects a boolean operand, found '%s'", operandType)
}
exprNode.ExprType = shared.PRIMITIVE_BOOL
return shared.PRIMITIVE_BOOL, nil
case parser.UNARY_OP_NEGATE:
if !shared.IsNumericType(operandType) {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Operand.GetLoc(), "unary operator '-' requires numeric operand, found '%s'", operandType)
}
exprNode.ExprType = operandType
return operandType, nil
case parser.UNARY_OP_DEREFERENCE:
if !operandType.IsPointer() {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Operand.GetLoc(), "unary operator '*' requires a pointer operand, found '%s'", operandType)
}
t := operandType.(shared.Pointer).To
exprNode.ExprType = t
return t, nil
case parser.UNARY_OP_REFERENCE:
identifier, ok := exprNode.Operand.(*parser.IdentifierNode)
if !ok {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Operand.GetLoc(), "unary operator '&' requires an identifier operand")
}
varName := identifier.Name
varSig, ok := tc.VarTable.Lookup(varName)
if !ok {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Operand.GetLoc(), "undefined variable '%s'", varName)
}
t := shared.Pointer{
To: operandType,
Const: !varSig.Mutable,
}
exprNode.ExprType = t
return t, nil
default:
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "unknown operator")
}
case *parser.BinaryOpNode:
leftType, err := tc.typeCheckExpression(exprNode.Operand1, shared.PRIMITIVE_VOID)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
rightType, err := tc.typeCheckExpression(exprNode.Operand2, shared.PRIMITIVE_VOID)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
if expectedType != shared.PRIMITIVE_VOID {
if leftType == shared.PRIMITIVE_UNTYPED_INT && shared.IsNumericType(expectedType) {
SetNodeType(exprNode.Operand1, expectedType)
leftType = expectedType
}
if rightType == shared.PRIMITIVE_UNTYPED_INT && shared.IsNumericType(expectedType) {
SetNodeType(exprNode.Operand2, expectedType)
rightType = expectedType
}
}
switch exprNode.Op {
case parser.BINARY_OP_LOGICAL_AND, parser.BINARY_OP_LOGICAL_OR:
if leftType != shared.PRIMITIVE_BOOL || rightType != shared.PRIMITIVE_BOOL {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "operator expects boolean operands")
}
exprNode.ExprType = shared.PRIMITIVE_BOOL
return shared.PRIMITIVE_BOOL, nil
case parser.BINARY_OP_EQUAL, parser.BINARY_OP_NOT_EQUAL,
parser.BINARY_OP_LESS, parser.BINARY_OP_LESS_EQUAL,
parser.BINARY_OP_GREATER, parser.BINARY_OP_GREATER_EQUAL:
if !shared.IsNumericType(leftType) || !shared.IsNumericType(rightType) {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "operator cannot be applied to operands")
}
exprNode.ExprType = shared.PRIMITIVE_BOOL
return shared.PRIMITIVE_BOOL, nil
case parser.BINARY_OP_ADD, parser.BINARY_OP_SUBTRACT,
parser.BINARY_OP_MULTIPLY, parser.BINARY_OP_DIVIDE,
parser.BINARY_OP_MODULO:
if !shared.IsNumericType(leftType) || !shared.IsNumericType(rightType) {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "operator requires numeric operands")
}
commonType := shared.BiggerNumericType(leftType, rightType)
SetNodeType(exprNode.Operand1, commonType)
SetNodeType(exprNode.Operand2, commonType)
exprNode.ExprType = commonType
return commonType, nil
default:
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "unknown operator")
}
case *parser.CastNode:
tpeName := exprNode.ToType.Name
tpe, ok := tc.TypeTable.Lookup(tpeName)
if !ok {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "no such type '%s'", tpeName)
}
exTpe, err := tc.typeCheckExpression(exprNode.Operand, shared.PRIMITIVE_VOID)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
if exTpe == shared.PRIMITIVE_UNTYPED_INT {
SetNodeType(exprNode.Operand, tpe)
}
if shared.CanCastTo(exTpe, tpe) {
exprNode.ExprType = tpe
return tpe, nil
} else {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "cannot cast type '%s' to '%s'", exTpe, tpe)
}
case *parser.IfExprNode:
condType, err := tc.typeCheckExpression(exprNode.IfBranch.Condition, shared.PRIMITIVE_BOOL)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
if condType != shared.PRIMITIVE_BOOL {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.IfBranch.Condition.GetLoc(), "if condition must be boolean, found '%s'", condType)
}
ifType, err := tc.typeCheckExpression(exprNode.IfBranch.Node, expectedType)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
commonType := ifType
for _, elseIf := range exprNode.ElseIfBranches {
elseIfCondType, err := tc.typeCheckExpression(elseIf.Condition, shared.PRIMITIVE_BOOL)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
if elseIfCondType != shared.PRIMITIVE_BOOL {
return shared.PRIMITIVE_VOID, shared.NewError(elseIf.Condition.GetLoc(), "else-if condition must be boolean, found '%s'", elseIfCondType)
}
elseIfType, err := tc.typeCheckExpression(elseIf.Node, expectedType)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
if elseIfType != commonType {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "all branches must return same type, expected '%s' but found '%s'", commonType, elseIfType)
}
}
elseType, err := tc.typeCheckExpression(exprNode.ElseBranch, expectedType)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
if elseType != commonType {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.ElseBranch.GetLoc(), "else branch must match type '%s', found '%s'", commonType, elseType)
}
exprNode.ExprType = commonType
return commonType, nil
case *parser.GivenExprNode:
_, err := tc.typeCheckBlock(exprNode.Block, nil, false, false)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
exprType, err := tc.typeCheckExpression(exprNode.FinalExpr, expectedType)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
exprNode.ExprType = exprType
return exprType, nil
case *parser.StructLiteralNode:
name := exprNode.Name.Name
structType, ok := tc.TypeTable.Lookup(name)
if !ok {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "no such struct type '%s'", name)
}
st, ok := structType.(shared.Struct)
if !ok {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "'%s' is not a struct type", name)
}
if len(st.Fields) != len(exprNode.Fields) {
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.Loc, "struct '%s' expects %d fields, got %d (zero values are not allowed)", name, len(st.Fields), len(exprNode.Fields))
}
for _, field := range exprNode.Fields {
var fieldType shared.Type = nil
for _, f := range st.Fields {
if f.L == field.L {
fieldType = f.R
}
}
if fieldType == nil {
return shared.PRIMITIVE_VOID, shared.NewError(field.R.GetLoc(), "struct '%s' has no field named '%s'", name, field.L)
}
exprType, err := tc.typeCheckExpression(field.R, fieldType)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
if !exprType.Compare(fieldType) {
return shared.PRIMITIVE_VOID, shared.NewError(field.R.GetLoc(), "field '%s' of struct '%s' expects type '%s', got '%s'", field.L, name, fieldType, exprType)
}
}
exprNode.ExprType = structType
return structType, nil
default:
return shared.PRIMITIVE_VOID, shared.NewError(exprNode.GetLoc(), "unsupported expression type")
}
}
func (tc *TypeChecker) typeCheckFunctionCall(funccallNode *parser.FunctionCallNode) (shared.Type, error) {
fname := funccallNode.Name.Name
fsig, ok := tc.FuncTable.Lookup(fname)
if !ok {
return shared.PRIMITIVE_VOID, shared.NewError(funccallNode.Name.Loc, "undefined function '%s'", fname)
}
if (len(funccallNode.Args) > len(fsig.ArgTypes) && !fsig.HasVariadic) || len(funccallNode.Args) < len(fsig.ArgTypes) {
return shared.PRIMITIVE_VOID, shared.NewError(funccallNode.Loc, "argument count mismatch, expected at least %d, got %d", len(fsig.ArgTypes), len(funccallNode.Args))
}
for i, arg := range funccallNode.Args {
var fsigArgType shared.Type = shared.PRIMITIVE_VOID
if i < len(fsig.ArgTypes) {
fsigArgType = fsig.ArgTypes[i].Type
}
argType, err := tc.typeCheckExpression(arg, fsigArgType)
if err != nil {
return shared.PRIMITIVE_VOID, err
}
if !fsigArgType.Compare(argType) && !fsigArgType.Compare(shared.PRIMITIVE_VOID) {
return shared.PRIMITIVE_VOID, shared.NewError(arg.GetLoc(),
"argument %d of function '%s' has type '%s' but expected '%s'",
i+1, fname, argType, fsigArgType,
)
}
}
funccallNode.ExprType = fsig.RetType
return fsig.RetType, nil
}
func (tc *TypeChecker) typeCheckDeclaration(declNode *parser.DeclarationNode) (string, *VarSig, error) {
if strings.HasPrefix(declNode.Name, "___") {
return "", nil, shared.NewError(declNode.Loc, "variables starting with '___' are reserved for the compiler")
}
mutable := declNode.Mutable
var varType shared.Type = shared.PRIMITIVE_VOID
if declNode.Type != nil {
varTypeStr := declNode.Type.Name
vt, ok := tc.TypeTable.Lookup(varTypeStr)
if !ok {
return "", nil, shared.NewError(declNode.Type.Loc, "variable '%s' has undefined type '%s'", declNode.Name, varTypeStr)
}
varType = vt
}
exprType, err := tc.typeCheckExpression(declNode.Value, varType)
if err != nil {
return "", nil, err
}
if varType == shared.PRIMITIVE_VOID {
varType = exprType
} else if !shared.CanCoerceTo(exprType, varType) {
return "", nil, shared.NewError(declNode.Loc,
"cannot assign value of type '%s' to variable '%s' of type '%s'",
exprType, declNode.Name, varType,
)
}
if varType == shared.PRIMITIVE_UNTYPED_INT {
varType = shared.PRIMITIVE_I32
SetNodeType(declNode.Value, varType)
exprType = shared.PRIMITIVE_I32
}
if varType == shared.PRIMITIVE_VOID {
return "", nil, shared.NewError(declNode.Loc, "a variable cannot be of type void")
}
return declNode.Name, &VarSig{
Type: varType,
Mutable: mutable,
}, nil
}
func (tc *TypeChecker) typeCheckAssignment(asNode *parser.AssignmentNode) error {
switch assignee := asNode.Assignee.(type) {
case *parser.IdentifierNode:
return tc.typeCheckIdentifierAssignment(asNode, assignee)
case *parser.UnaryOpNode:
if assignee.Op == parser.UNARY_OP_DEREFERENCE {
return tc.typeCheckPointerAssignment(asNode, assignee)
}
}
return shared.NewError(asNode.Assignee.GetLoc(), "left side of assignment must be a variable or dereferenced pointer")
}
func (tc *TypeChecker) typeCheckIdentifierAssignment(asNode *parser.AssignmentNode, assignee *parser.IdentifierNode) error {
varName := assignee.Name
varSig, ok := tc.VarTable.Lookup(varName)
if !ok {
return shared.NewError(assignee.Loc, "undefined variable '%s'", varName)
}
if !varSig.Mutable {
return shared.NewError(asNode.Loc, "cannot assign to immutable variable '%s'", varName)
}
currType, err := ResolveFieldChain(assignee, varSig.Type)
if err != nil {
return err
}
exprType, err := tc.typeCheckExpression(asNode.Value, currType)
if err != nil {
return err
}
if exprType != currType {
return shared.NewError(asNode.Loc,
"cannot assign value of type '%s' to variable '%s' of type '%s'",
exprType, varName, varSig.Type,
)
}
return nil
}
func (tc *TypeChecker) typeCheckPointerAssignment(asNode *parser.AssignmentNode, assignee *parser.UnaryOpNode) error {
switch ident := assignee.Operand.(type) {
case *parser.IdentifierNode:
ptrType, err := tc.typeCheckExpression(assignee.Operand, shared.PRIMITIVE_VOID)
if err != nil {
return err
}
if !ptrType.IsPointer() {
return shared.NewError(assignee.Loc, "left side of assignment must be a pointer, found '%s'", ptrType)
}
ptr := ptrType.(shared.Pointer)
if ptr.Const {
return shared.NewError(assignee.Loc, "cannot perform pointer assignment if the pointee is immutable")
}
currType, err := ResolveFieldChain(ident, ptr.To)
if err != nil {
return err
}
exprType, err := tc.typeCheckExpression(asNode.Value, currType)
if err != nil {
return err
}
if exprType != currType {
return shared.NewError(asNode.Loc,
"cannot assign value of type '%s' to variable of type '%s'",
exprType, currType,
)
}
default:
return shared.NewError(assignee.Operand.GetLoc(), "left side of assignment must be a pointer to a variable")
}
return nil
}
func (tc *TypeChecker) typeCheckForLoop(loopNode *parser.ForNode, sig *FunctionSig) error {
tc.enterScope()
if len(loopNode.ExprsOrStmts) == 1 {
condMb := loopNode.ExprsOrStmts[0]
if _, ok := condMb.(parser.ExpressionNode); !ok {
return shared.NewError(condMb.GetLoc(), "for loop condition must be a boolean expression")
}
cond := condMb.(parser.ExpressionNode)
exprType, err := tc.typeCheckExpression(cond, shared.PRIMITIVE_BOOL)
if err != nil {
return err
}
if exprType != shared.PRIMITIVE_BOOL {
return shared.NewError(cond.GetLoc(), "for loop condition must be a boolean expression, found '%s'", exprType)
}
} else if len(loopNode.ExprsOrStmts) == 3 {
switch init := loopNode.ExprsOrStmts[0].(type) {
case *parser.DeclarationNode:
varName, varSig, err := tc.typeCheckDeclaration(init)
if err != nil {
return err
}
tc.VarTable.Define(varName, varSig)
case *parser.AssignmentNode:
if err := tc.typeCheckAssignment(init); err != nil {
return err
}
default:
return shared.NewError(init.GetLoc(), "for loop initialiser must be a declaration or assignment statement")
}
condMb := loopNode.ExprsOrStmts[1]
if _, ok := condMb.(parser.ExpressionNode); !ok {
return shared.NewError(condMb.GetLoc(), "for loop condition must be a boolean expression")
}
cond := condMb.(parser.ExpressionNode)
exprType, err := tc.typeCheckExpression(cond, shared.PRIMITIVE_BOOL)
if err != nil {
return err
}
if exprType != shared.PRIMITIVE_BOOL {
return shared.NewError(cond.GetLoc(), "for loop condition must be a boolean expression, found '%s'", exprType)
}
switch reass := loopNode.ExprsOrStmts[2].(type) {
case *parser.AssignmentNode:
if err := tc.typeCheckAssignment(reass); err != nil {
return err
}
default:
return shared.NewError(reass.GetLoc(), "for loop 'after' step must be an assignment statement")
}
} else if len(loopNode.ExprsOrStmts) != 0 {
return shared.NewError(loopNode.Loc, "for loop must have either: no conditions, one condition or an initialiser, a condition and an 'after' assignment")
}
if _, err := tc.typeCheckBlock(loopNode.Body, sig, true, false); err != nil {
return err
}
tc.exitScope()
return nil
}
func (tc *TypeChecker) typeCheckIfStatement(ifNode *parser.IfNode, sig *FunctionSig, isLoop bool) (bool, error) {
ifCondType, err := tc.typeCheckExpression(ifNode.IfBranch.Condition, shared.PRIMITIVE_BOOL)
if err != nil {
return false, err
}
if ifCondType != shared.PRIMITIVE_BOOL {
return false, shared.NewError(ifNode.IfBranch.Condition.GetLoc(), "if condition must be boolean, found '%s'", ifCondType)
}
ifReturns, err := tc.typeCheckBlock(ifNode.IfBranch.Node, sig, isLoop, false)
if err != nil {
return false, err
}
alwaysReturns := ifReturns && ifNode.ElseBranch != nil
for _, elseIfBranch := range ifNode.ElseIfBranches {
elseIfCondType, err := tc.typeCheckExpression(elseIfBranch.Condition, shared.PRIMITIVE_BOOL)
if err != nil {
return false, err
}
if elseIfCondType != shared.PRIMITIVE_BOOL {
return false, shared.NewError(elseIfBranch.Condition.GetLoc(), "else-if condition must be boolean, found '%s'", elseIfCondType)
}
elseIfReturns, err := tc.typeCheckBlock(elseIfBranch.Node, sig, isLoop, false)
if err != nil {
return false, err
}
if !alwaysReturns {
alwaysReturns = elseIfReturns
}
}
if ifNode.ElseBranch != nil {
elseReturns, err := tc.typeCheckBlock(ifNode.ElseBranch, sig, isLoop, false)
if err != nil {
return false, err
}
if !alwaysReturns {
alwaysReturns = elseReturns
}
}
return alwaysReturns, nil
}
func ResolveFieldChain(field *parser.IdentifierNode, tpe shared.Type) (shared.Type, error) {
field.ExprType = tpe
if field.Next == nil {
return tpe, nil
}
var strct shared.Struct
if tpe.IsStruct() {
strct = tpe.(shared.Struct)
} else if tpe.IsPointer() && tpe.(shared.Pointer).To.IsStruct() {
strct = tpe.(shared.Pointer).To.(shared.Struct)
}
for _, f := range strct.Fields {
if f.L == field.Next.Name {
return ResolveFieldChain(field.Next, f.R)
}
}
return nil, shared.NewError(field.Next.Loc, "type has no field named '%s'", field.Next.Name)
}
func (tc *TypeChecker) ExtractFunctionSig(functionNode *parser.FunctionDefNode) (*FunctionSig, error) {
var retType shared.Type
if (functionNode.RetType != nil) {
retTypeStr := functionNode.RetType.Name
r, ok := tc.TypeTable.Lookup(retTypeStr)
if !ok {
return nil, shared.NewError(functionNode.RetType.Loc, "function '%s' has undefined return type '%s'", functionNode.Name, retTypeStr)
}
retType = r
} else {
if functionNode.Name == "main" {
retType = shared.PRIMITIVE_I32
} else {
retType = shared.PRIMITIVE_VOID
}
}
argTypes := make([]FunctionSigArg, len(functionNode.Args))
for i, arg := range functionNode.Args {
tpe := arg.Type.Name
resolved, ok := tc.TypeTable.Lookup(tpe)
if !ok {
return nil, shared.NewError(arg.Type.Loc, "parameter '%s' has undefined type '%s'", arg.Name, tpe)
}
for i := arg.PointerLevel; i > 0; i-- {
resolved = shared.Pointer{
To: resolved,
}
}
argTypes[i] = FunctionSigArg{
Name: arg.Name,
Type: resolved,
Mutable: arg.Mutable,
}
}
return &FunctionSig{
ArgTypes: argTypes,
RetType: retType,
Name: functionNode.Name,
HasVariadic: functionNode.HasVariadic,
}, nil
}
func SetNodeType(n parser.ExpressionNode, t shared.Type) {
switch node := n.(type) {
case *parser.IdentifierNode:
node.ExprType = t
case *parser.BoolLiteralNode:
node.ExprType = t
case *parser.NumberLiteralNode:
node.ExprType = t
case *parser.StringLiteralNode:
node.ExprType = t
case *parser.CharLiteralNode:
node.ExprType = t
case *parser.StructLiteralNode:
node.ExprType = t
case *parser.FunctionCallNode:
node.ExprType = t
case *parser.IfExprNode:
node.ExprType = t
case *parser.GivenExprNode:
node.ExprType = t
case *parser.UnaryOpNode:
node.ExprType = t
case *parser.BinaryOpNode:
node.ExprType = t
case *parser.CastNode:
node.ExprType = t
default:
panic("SetNodeType: unknown node type")
}
}