make compiler errors general, and better imports

core/compiler.go

@@ -1,7 +1,6 @@
 package core
 
 import (
-	"errors"
 	"fmt"
 	"strings"
 )
@@ -21,8 +20,13 @@ type Compiler struct {
 	stack *Stack[LocalVariable]
 }
 
+type ImportResult struct {
+	Source string
+	Path   string
+}
+
 type ImportsResolver interface {
-	Resolve(path string) (string, error)
+	Resolve(from, path string) (*ImportResult, error)
 	IsSame(a, b string) bool
 }
 
@@ -34,7 +38,7 @@ type LocalVariable struct {
 
 type CompilerError struct {
 	Description string
-	Causer      Node
+	Boundary    Boundary
 	Source      []rune
 	Trace       []string
 }
@@ -51,7 +55,7 @@ func (e CompilerError) Format() string {
 	b.WriteString(e.Description)
 
 	// highlight offending area
-	start, end := e.Causer.Bounds()
+	start, end := e.Boundary.Bounds()
 
 	lineEnd := 0
 	lineStart := 0
@@ -1254,7 +1258,7 @@ func (c *Compiler) addDescend() {
 	c.add(InstructionDescend)
 }
 
-func (c *Compiler) error(msg string, causer Node) CompilerError {
+func (c *Compiler) error(msg string, causer Boundary) CompilerError {
 	return CompilerError{
 		msg,
 		causer,
@@ -1267,34 +1271,34 @@ func (c *Compiler) warn(msg string, causer Node) {
 	c.Warnings = append(c.Warnings, c.error(msg, causer))
 }
 
-func (c *Compiler) resolveImport(path string) error {
+func (c *Compiler) resolveImport(imp Import) error {
+	res, err := c.resolver.Resolve(c.fileStack.Peek(), imp.path)
+	if err != nil {
+		return err
+	}
+
 	// if already imported and available
 	for _, i := range c.imports {
-		if c.resolver.IsSame(path, i) {
+		if c.resolver.IsSame(res.Path, i) {
 			return nil
 		}
 	}
 
 	// stop recursive imports
 	for i := c.fileStack.Current - 1; i >= 0; i-- {
-		if c.resolver.IsSame(path, c.fileStack.items[i]) {
-			return errors.New("recursive import")
+		if c.resolver.IsSame(res.Path, c.fileStack.items[i]) {
+			return c.error("recursive import", imp)
 		}
 	}
 
-	src, err := c.resolver.Resolve(path)
-	if err != nil {
-		return err
-	}
-
-	l := NewLexer(src)
+	l := NewLexer(res.Source)
 	tokens, err := l.Tokenize()
 	if err != nil {
 		return err
 	}
 
-	parser := NewParser(src, append(c.fileStack.Slice(), path), tokens)
-	p, err := parser.Parse(path)
+	parser := NewParser(res.Source, append(c.fileStack.Slice(), res.Path), tokens)
+	p, err := parser.Parse(res.Path)
 	if err != nil {
 		return err
 	}
@@ -1302,7 +1306,7 @@ func (c *Compiler) resolveImport(path string) error {
 	oldSrc := c.source
 
 	// update source for more descriptive errors
-	c.source = []rune(src)
+	c.source = []rune(res.Source)
 	if err := c.Compile(p); err != nil {
 		return err
 	}