Simplified file structure

src/core/CompileCall.go

@@ -0,0 +1,109 @@
+package core
+
+import (
+	"strings"
+
+	"git.akyoto.dev/cli/q/src/asm"
+	"git.akyoto.dev/cli/q/src/errors"
+	"git.akyoto.dev/cli/q/src/expression"
+)
+
+// CompileCall executes a function call.
+// All call registers must hold the correct parameter values before the function invocation.
+// Registers that are in use must be saved if they are modified by the function.
+// After the function call, they must be restored in reverse order.
+func (f *Function) CompileCall(root *expression.Expression) (*Function, error) {
+	var (
+		pkg      = f.Package
+		nameNode = root.Children[0]
+		fn       *Function
+		name     string
+		fullName string
+		exists   bool
+	)
+
+	if nameNode.IsLeaf() {
+		name = nameNode.Token.Text(f.File.Bytes)
+
+		if name == "syscall" {
+			return nil, f.CompileSyscall(root)
+		}
+	} else {
+		pkg = nameNode.Children[0].Token.Text(f.File.Bytes)
+		name = nameNode.Children[1].Token.Text(f.File.Bytes)
+	}
+
+	if pkg != f.File.Package {
+		if f.File.Imports == nil {
+			return nil, errors.New(&errors.UnknownPackage{Name: pkg}, f.File, nameNode.Token.Position)
+		}
+
+		imp, exists := f.File.Imports[pkg]
+
+		if !exists {
+			return nil, errors.New(&errors.UnknownPackage{Name: pkg}, f.File, nameNode.Token.Position)
+		}
+
+		imp.Used = true
+	}
+
+	tmp := strings.Builder{}
+	tmp.WriteString(pkg)
+	tmp.WriteString(".")
+	tmp.WriteString(name)
+	fullName = tmp.String()
+	fn, exists = f.Functions[fullName]
+
+	if !exists {
+		return nil, errors.New(&errors.UnknownFunction{Name: name}, f.File, nameNode.Token.Position)
+	}
+
+	parameters := root.Children[1:]
+	registers := f.CPU.Input[:len(parameters)]
+
+	for i := len(parameters) - 1; i >= 0; i-- {
+		typ, err := f.ExpressionToRegister(parameters[i], registers[i])
+
+		if err != nil {
+			return nil, err
+		}
+
+		if typ != fn.Parameters[i].Type {
+			return nil, errors.New(&errors.TypeMismatch{
+				Encountered:   string(typ),
+				Expected:      string(fn.Parameters[i].Type),
+				ParameterName: fn.Parameters[i].Name,
+			}, f.File, parameters[i].Token.Position)
+		}
+	}
+
+	for _, register := range f.CPU.Output[:len(fn.ReturnTypes)] {
+		f.SaveRegister(register)
+	}
+
+	for _, register := range f.CPU.General {
+		if f.RegisterIsUsed(register) {
+			f.Register(asm.PUSH, register)
+		}
+	}
+
+	f.Call(fullName)
+
+	for _, register := range registers {
+		if register == f.CPU.Output[0] && root.Parent != nil {
+			continue
+		}
+
+		f.FreeRegister(register)
+	}
+
+	for i := len(f.CPU.General) - 1; i >= 0; i-- {
+		register := f.CPU.General[i]
+
+		if f.RegisterIsUsed(register) {
+			f.Register(asm.POP, register)
+		}
+	}
+
+	return fn, nil
+}