[Bootstrap] Update the call stack to container the caller and add a line index to the parser

bootstrap/pkg/ast/ast.go

@@ -53,23 +53,65 @@ type Source struct {
 	LineIndex *[]int
 }
 
+func (s *Source) GetPos(start, end int) *string {
+	if start < len(*s.Buffer) && start >= 0 && end < len(*s.Buffer) && end > 0 && start <= end {
+		result := strings.Join((*s.Buffer)[start:end], "")
+		return &result
+	} else {
+		return nil
+	}
+}
 func (s *Source) GetLine(linenum int) string {
 	lines := strings.Split(strings.Join(*s.Buffer, ""), "\n")
-	return lines[linenum-1]
+	if linenum > 0 && linenum < len(lines) {
+		return lines[linenum-1]
+	}
+	return "!!!"
 }
 
 func (s *Source) LineNumberFor(pos int) int {
+
+	// Some dirty print debugger code
+	// for i, r := range *s.LineIndex {
+	// 	empty := ""
+	// 	var line *string
+	// 	var num int
+	// 	if i == 0 {
+	// 		line = s.GetPos(0, r)
+	// 		num = 0
+	// 	} else {
+	// 		line = s.GetPos((*s.LineIndex)[i-1], r)
+	// 		num = (*s.LineIndex)[i-1]
+
+	// 	}
+
+	// 	if line == nil {
+	// 		line = &empty
+	// 	}
+
+	// 	fmt.Print(">>>> ", num, r, *line)
+	// }
+
 	if pos < 0 {
 		return -1
 	}
 
-	return sort.Search(len(*s.LineIndex), func(i int) bool {
+	result := sort.Search(len(*s.LineIndex), func(i int) bool {
 		if i == 0 {
 			return pos < (*s.LineIndex)[i]
 		} else {
 			return (*s.LineIndex)[i-1] < pos && pos < (*s.LineIndex)[i]
 		}
 	})
+
+	// We've found something
+	if result > -1 {
+		// Since line numbers start from 1 unlike arrays :))
+		result += 1
+	}
+
+	return result
+
 }
 
 type Location struct {

bootstrap/pkg/core/call_stack.go

@@ -52,7 +52,7 @@ type Frame struct {
 	Caller IExpr
 }
 
-type TraceBack = []Frame
+type TraceBack = []*Frame
 
 type CallStackItem struct {
 	prev *CallStackItem
@@ -158,7 +158,7 @@ func (c *CallStack) ToTraceBack() *TraceBack {
 		if item == nil {
 			break
 		}
-		tr = append(tr, item.data)
+		tr = append(tr, &item.data)
 		item = item.prev
 	}
 
@@ -172,3 +172,11 @@ func MakeCallStack(debugMode bool) CallStack {
 		debug: debugMode,
 	}
 }
+
+func MakeFrame(caller IExpr, f IFn, count uint) *Frame {
+	return &Frame{
+		Count:  count,
+		Caller: caller,
+		Fn:     f,
+	}
+}

bootstrap/pkg/core/errors.go

@@ -38,6 +38,7 @@ import (
 	"fmt"
 
 	"serene-lang.org/bootstrap/pkg/ast"
+	"serene-lang.org/bootstrap/pkg/errors"
 )
 
 // IError defines the necessary functionality of the internal errors.
@@ -49,6 +50,7 @@ type IError interface {
 	IRepresentable
 	IDebuggable
 
+	GetDescription() *string
 	GetStackTrace() *TraceBack
 	// To wrap Golan rrrrors
 	WithError(err error) IError
@@ -61,6 +63,7 @@ type IError interface {
 
 type Error struct {
 	Node
+	errno      errors.Errno
 	WrappedErr error
 	msg        string
 	trace      *TraceBack
@@ -95,6 +98,16 @@ func (e *Error) GetStackTrace() *TraceBack {
 	return e.trace
 }
 
+func (e *Error) GetDescription() *string {
+	desc, ok := errors.ErrorsDescription[e.errno]
+	if ok {
+		return &desc
+	}
+
+	desc = errors.ErrorsDescription[0]
+	return &desc
+}
+
 func MakePlainError(msg string) IError {
 	return &Error{
 		msg: msg,
@@ -104,7 +117,7 @@ func MakePlainError(msg string) IError {
 // MakeError creates an Error which points to the given IExpr `e` as
 // the root of the error.
 func MakeError(rt *Runtime, e IExpr, msg string) IError {
-	trace := append(*rt.Stack.ToTraceBack(), Frame{0, rt.Stack.GetCurrentFn(), e})
+	trace := append(*rt.Stack.ToTraceBack(), &Frame{0, rt.Stack.GetCurrentFn(), e})
 
 	return &Error{
 		Node:  MakeNodeFromExpr(e),
@@ -119,3 +132,18 @@ func MakeParsetimeErrorf(n Node, msg string, a ...interface{}) IError {
 		msg:  fmt.Sprintf(msg, a...),
 	}
 }
+
+func MakeSemanticError(rt *Runtime, e IExpr, errno errors.Errno, msg string) IError {
+	currentFn := rt.Stack.GetCurrentFn()
+
+	frames := &[]*Frame{
+		MakeFrame(e, currentFn, 1),
+	}
+
+	return &Error{
+		Node:  MakeNodeFromExpr(e),
+		errno: errno,
+		msg:   msg,
+		trace: frames,
+	}
+}

bootstrap/pkg/core/eval.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 
 	"serene-lang.org/bootstrap/pkg/ast"
+	"serene-lang.org/bootstrap/pkg/errors"
 )
 
 func restOfExprs(es []IExpr, i int) []IExpr {
@@ -623,7 +624,12 @@ func EvalNSBody(rt *Runtime, ns *Namespace) (*Namespace, IError) {
 	exprs := body.ToSlice()
 
 	if len(exprs) == 0 {
-		return nil, MakeError(rt, ns, fmt.Sprintf("the 'ns' form is missing from '%s'", ns.GetName()))
+		return nil, MakeSemanticError(
+			rt,
+			ns,
+			errors.E0001,
+			fmt.Sprintf("the 'ns' form is missing from '%s'", ns.GetName()),
+		)
 	}
 
 	if exprs[0].GetType() == ast.List {

bootstrap/pkg/core/function.go

@@ -42,6 +42,7 @@ import (
 	"fmt"
 
 	"serene-lang.org/bootstrap/pkg/ast"
+	"serene-lang.org/bootstrap/pkg/errors"
 	"serene-lang.org/bootstrap/pkg/hash"
 )
 
@@ -175,9 +176,12 @@ func MakeFnScope(rt *Runtime, parent IScope, bindings IColl, values IColl) (*Sco
 			fmt.Printf("[DEBUG] Mismatch on bindings and values: Bindings: %s, Values: %s\n", bindings, values)
 		}
 
-		fmt.Println("3333333", values.(IExpr).GetLocation(), bindings.(IExpr).GetLocation())
-		return nil, MakeError(rt, values.(IExpr),
-			fmt.Sprintf("expected '%d' arguments, got '%d'.", bindings.Count(), values.Count()))
+		return nil, MakeSemanticError(
+			rt,
+			values.(IExpr),
+			errors.E0002,
+			fmt.Sprintf("expected '%d' arguments, got '%d'.", bindings.Count(), values.Count()),
+		)
 	}
 
 	for i := 0; i < len(binds); i += 1 {

bootstrap/pkg/core/parser.go

@@ -66,26 +66,45 @@ type IParsable interface {
 // StringParser is an implementation of the  IParsable that operates on strings.
 // To put it simply it parses input strings
 type StringParser struct {
-	buffer    []string
-	pos       int
-	source    string
+	buffer []string
+	pos    int
+	source string
+
+	// This slice holds the boundaries of lines in the buffer. Basically
+	// each element determines the position which a line ends and the line
+	// number directly maps to the position of it's boundary in the slice.
 	lineIndex []int
 }
 
 // Implementing IParsable for StringParser ---
 
+// updateLineIndex reads the current character and if it is an end of line, then
+// it will update the line index to add the boundaries of the current line.
+func (sp *StringParser) updateLineIndex(pos int) {
+	if pos < len(sp.buffer) {
+		c := sp.buffer[pos]
+		if c == "\n" {
+			if len(sp.lineIndex) > 0 {
+				if sp.lineIndex[len(sp.lineIndex)-1] != pos+1 {
+					// Including the \n itself
+					sp.lineIndex = append(sp.lineIndex, pos+1)
+				}
+			} else {
+				sp.lineIndex = append(sp.lineIndex, pos+1)
+			}
+
+		}
+	}
+
+}
+
 // Returns the next character in the buffer
 func (sp *StringParser) next(skipWhitespace bool) *string {
 	if sp.pos >= len(sp.buffer) {
 		return nil
 	}
 	char := sp.buffer[sp.pos]
-
-	if char == "\n" {
-		// Including the \n itself
-		sp.lineIndex = append(sp.lineIndex, sp.pos+1)
-	}
-
+	sp.updateLineIndex(sp.pos)
 	sp.pos = sp.pos + 1
 
 	if skipWhitespace && isSeparator(&char) {
@@ -121,6 +140,7 @@ func (sp *StringParser) peek(skipWhitespace bool) *string {
 
 	c := sp.buffer[sp.pos]
 	if isSeparator(&c) && skipWhitespace {
+		sp.updateLineIndex(sp.pos)
 		sp.pos = sp.pos + 1
 		return sp.peek(skipWhitespace)
 	}

bootstrap/pkg/core/printer.go

@@ -67,29 +67,29 @@ func Println(rt *Runtime, ast ...IRepresentable) {
 func PrintError(rt *Runtime, err IError) {
 	trace := err.GetStackTrace()
 
-	for i, f := range *trace {
-		loc := f.Caller.GetLocation()
-		fmt.Println("===============")
-		fmt.Println(f.Fn.GetLocation())
-		fmt.Println(loc)
-		source := loc.GetSource()
-		// if loc.GetSource().Buffer != nil {
-		// 	fmt.Println(loc.GetSource().LineIndex)
-		// 	source = *loc.GetSource().Buffer
-		// }
-		startline := source.LineNumberFor(loc.GetStart()) - 1
-		endline := source.LineNumberFor(loc.GetEnd()) + 1
+	for i, t := range *trace {
+		caller := t.Caller
+		callerLoc := caller.GetLocation()
+		callerSource := callerLoc.GetSource()
+
+		startline := callerSource.LineNumberFor(callerLoc.GetStart())
+
+		if startline > 0 {
+			startline -= 1
+		}
+
+		endline := callerSource.LineNumberFor(callerLoc.GetEnd()) + 1
 
 		var lines string
 		for i := startline; i <= endline; i++ {
-			lines += fmt.Sprintf("%d:\t%s\n", i, source.GetLine(i))
+			lines += fmt.Sprintf("%d:\t%s\n", i, t.Fn.GetLocation().GetSource().GetLine(i))
 		}
 
 		color.Yellow.Printf(
 			"%d: In function '%s' at '%s'\n",
 			i,
-			f.Fn.GetName(),
-			loc.GetSource().Path,
+			t.Fn.GetName(),
+			callerLoc.GetSource().Path,
 		)
 		color.White.Printf("%s\n", lines)
 	}