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feat: better error messages

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This commit is contained in:
Maxim Hutz
2025-12-27 02:39:56 -05:00
parent 884180de92
commit 1896cd652d
6 changed files with 70 additions and 51 deletions
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42
pkg/saccharine/parser.go
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@@ -1,12 +1,12 @@
package saccharine
import (
"errors"
"fmt"
"git.maximhutz.com/max/lambda/pkg/iterator"
"git.maximhutz.com/max/lambda/pkg/saccharine/ast"
"git.maximhutz.com/max/lambda/pkg/saccharine/token"
"git.maximhutz.com/max/lambda/pkg/trace"
)
type TokenIterator = iterator.Iterator[token.Token]
@@ -25,15 +25,22 @@ func parseToken(i *TokenIterator, expected token.Type) (*token.Token, error) {
}
func parseExpression(i *TokenIterator) (ast.Expression, error) {
if abs, absErr := parseAbstraction(i); absErr == nil {
return abs, nil
} else if atm, atmErr := parseApplication(i); atmErr == nil {
return atm, nil
} else if app, appErr := parseAtom(i); appErr == nil {
return app, nil
} else {
return nil, errors.Join(absErr, appErr, atmErr)
var err error
var exp ast.Expression
peek := i.MustGet()
switch peek.Type {
case token.OpenParen:
exp, err = parseApplication(i)
case token.Slash:
exp, err = parseAbstraction(i)
case token.Atom:
exp, err = parseAtom(i)
default:
return nil, fmt.Errorf("expected expression, got '%v' (col %d)", peek.Value, peek.Index)
}
return exp, err
}
func parseParameters(i *TokenIterator) ([]string, error) {
@@ -56,11 +63,11 @@ func parseAbstraction(i *TokenIterator) (*ast.Abstraction, error) {
i2 := i.Copy()
if _, err := parseToken(i2, token.Slash); err != nil {
return nil, fmt.Errorf("no function slash (col %d): %w", i2.MustGet().Index, err)
return nil, trace.WrapError(fmt.Errorf("no function slash (col %d)", i2.MustGet().Index), err)
} else if parameters, err := parseParameters(i2); err != nil {
return nil, err
} else if _, err = parseToken(i2, token.Dot); err != nil {
return nil, fmt.Errorf("no function dot (col %d): %w", i2.MustGet().Index, err)
return nil, trace.WrapError(fmt.Errorf("no function dot (col %d)", i2.MustGet().Index), err)
} else if body, err := parseExpression(i2); err != nil {
return nil, err
} else {
@@ -74,11 +81,14 @@ func parseApplication(i *TokenIterator) (*ast.Application, error) {
expressions := []ast.Expression{}
if _, err := parseToken(i2, token.OpenParen); err != nil {
return nil, fmt.Errorf("no openning brackets (col %d): %w", i2.MustGet().Index, err)
return nil, trace.WrapError(fmt.Errorf("no openning brackets (col %d)", i2.MustGet().Index), err)
}
for {
if exp, err := parseExpression(i2); err != nil {
if len(expressions) == 0 {
return nil, trace.WrapError(fmt.Errorf("application has no arguments"), err)
}
break
} else {
expressions = append(expressions, exp)
@@ -86,11 +96,7 @@ func parseApplication(i *TokenIterator) (*ast.Application, error) {
}
if _, err := parseToken(i2, token.CloseParen); err != nil {
return nil, fmt.Errorf("no closing brackets (col %d): %w", i2.MustGet().Index, err)
}
if len(expressions) == 0 {
return nil, fmt.Errorf("application has no arguments")
return nil, trace.WrapError(fmt.Errorf("no closing brackets (col %d)", i2.MustGet().Index), err)
}
i.Sync(i2)
@@ -99,7 +105,7 @@ func parseApplication(i *TokenIterator) (*ast.Application, error) {
func parseAtom(i *TokenIterator) (*ast.Atom, error) {
if tok, err := parseToken(i, token.Atom); err != nil {
return nil, fmt.Errorf("no variable (col %d): %w", i.Index(), err)
return nil, trace.WrapError(fmt.Errorf("no variable (col %d)", i.Index()), err)
} else {
return ast.NewAtom(tok.Value), nil
}