Implemented extern functions

src/core/BeforeCall.go

@@ -0,0 +1,32 @@
+package core
+
+import (
+	"git.akyoto.dev/cli/q/src/cpu"
+	"git.akyoto.dev/cli/q/src/errors"
+	"git.akyoto.dev/cli/q/src/expression"
+	"git.akyoto.dev/cli/q/src/token"
+	"git.akyoto.dev/cli/q/src/types"
+)
+
+// BeforeCall loads the registers with the parameter values and checks that the types match with the function signature.
+func (f *Function) BeforeCall(fn *Function, parameters []*expression.Expression, registers []cpu.Register) error {
+	for i := len(parameters) - 1; i >= 0; i-- {
+		typ, err := f.ExpressionToRegister(parameters[i], registers[i])
+
+		if err != nil {
+			return err
+		}
+
+		if !types.Is(typ, fn.Input[i].Type) {
+			_, expectsPointer := fn.Input[i].Type.(*types.Pointer)
+
+			if expectsPointer && parameters[i].Token.Kind == token.Number && parameters[i].Token.Text(f.File.Bytes) == "0" {
+				continue
+			}
+
+			return errors.New(&errors.TypeMismatch{Encountered: typ.Name(), Expected: fn.Input[i].Type.Name(), ParameterName: fn.Input[i].Name}, f.File, parameters[i].Token.Position)
+		}
+	}
+
+	return nil
+}

src/core/CompileCall.go

@@ -5,7 +5,6 @@ import (
 
 	"git.akyoto.dev/cli/q/src/errors"
 	"git.akyoto.dev/cli/q/src/expression"
-	"git.akyoto.dev/cli/q/src/token"
 	"git.akyoto.dev/cli/q/src/types"
 	"git.akyoto.dev/cli/q/src/x86"
 )
@@ -48,22 +47,13 @@ func (f *Function) CompileCall(root *expression.Expression) ([]types.Type, error
 		name = nameNode.Token.Text(f.File.Bytes)
 	}
 
-	if pkg == "kernel32" || pkg == "user32" || pkg == "gdi32" || pkg == "comctl32" {
-		parameters := root.Children[1:]
-		registers := x86.WindowsInputRegisters[:len(parameters)]
+	fn, exists = f.Functions[pkg+"."+name]
 
-		for i := len(parameters) - 1; i >= 0; i-- {
-			_, err := f.ExpressionToRegister(parameters[i], registers[i])
+	if !exists {
+		return nil, errors.New(&errors.UnknownFunction{Name: name}, f.File, nameNode.Token.Position)
+	}
 
-			if err != nil {
-				return nil, err
-			}
-		}
-
-		f.DLLs = f.DLLs.Append(pkg, name)
-		f.DLLCall(fmt.Sprintf("%s.%s", pkg, name))
-		return nil, nil
-	} else if pkg != f.File.Package {
+	if pkg != f.File.Package && !fn.IsExtern() {
 		if f.File.Imports == nil {
 			return nil, errors.New(&errors.UnknownPackage{Name: pkg}, f.File, pkgNode.Token.Position)
 		}
@@ -77,36 +67,30 @@ func (f *Function) CompileCall(root *expression.Expression) ([]types.Type, error
 		imp.Used = true
 	}
 
-	fn, exists = f.Functions[pkg+"."+name]
-
-	if !exists {
-		return nil, errors.New(&errors.UnknownFunction{Name: name}, f.File, nameNode.Token.Position)
-	}
-
 	parameters := root.Children[1:]
 
 	if len(parameters) != len(fn.Input) {
 		return nil, errors.New(&errors.ParameterCountMismatch{Function: fn.Name, Count: len(parameters), ExpectedCount: len(fn.Input)}, f.File, nameNode.Token.End())
 	}
 
-	registers := f.CPU.Input[:len(parameters)]
-
-	for i := len(parameters) - 1; i >= 0; i-- {
-		typ, err := f.ExpressionToRegister(parameters[i], registers[i])
+	if fn.IsExtern() {
+		f.DLLs = f.DLLs.Append(pkg, name)
+		registers := x86.WindowsInputRegisters[:len(parameters)]
+		err := f.BeforeCall(fn, parameters, registers)
 
 		if err != nil {
 			return nil, err
 		}
 
-		if !types.Is(typ, fn.Input[i].Type) {
-			_, expectsPointer := fn.Input[i].Type.(*types.Pointer)
+		f.DLLCall(fmt.Sprintf("%s.%s", pkg, name))
+		return fn.OutputTypes, nil
+	}
 
-			if expectsPointer && parameters[i].Token.Kind == token.Number && parameters[i].Token.Text(f.File.Bytes) == "0" {
-				continue
-			}
+	registers := f.CPU.Input[:len(parameters)]
+	err := f.BeforeCall(fn, parameters, registers)
 
-			return nil, errors.New(&errors.TypeMismatch{Encountered: typ.Name(), Expected: fn.Input[i].Type.Name(), ParameterName: fn.Input[i].Name}, f.File, parameters[i].Token.Position)
-		}
+	if err != nil {
+		return nil, err
 	}
 
 	f.CallSafe(fn, registers)

src/core/IsExtern.go

@@ -0,0 +1,6 @@
+package core
+
+// IsExtern returns true if the function has no body.
+func (f *Function) IsExtern() bool {
+	return f.Body == nil
+}

src/core/ResolveTypes.go

@@ -19,6 +19,10 @@ func (f *Function) ResolveTypes() error {
 			return errors.New(&errors.UnknownType{Name: typeName}, f.File, param.tokens[1].Position)
 		}
 
+		if f.IsExtern() {
+			continue
+		}
+
 		uses := token.Count(f.Body, f.File.Bytes, token.Identifier, param.Name)
 
 		if uses == 0 && param.Name != "_" {
@@ -38,7 +42,7 @@ func (f *Function) ResolveTypes() error {
 		param.Type = types.ByName(typeName, f.Package, f.Structs)
 
 		if param.Type == nil {
-			return errors.New(&errors.UnknownType{Name: typeName}, f.File, param.tokens[1].Position)
+			return errors.New(&errors.UnknownType{Name: typeName}, f.File, param.tokens[0].Position)
 		}
 
 		f.OutputTypes = append(f.OutputTypes, param.Type)