Add error line number

parser/config.go

@@ -5,10 +5,12 @@ import "github.com/osteele/liquid/expression"
 // A Config holds configuration information for parsing and rendering.
 type Config struct {
 	expression.Config
-	Grammar Grammar
+	Grammar  Grammar
+	Filename string
+	LineNo   int
 }
 
 // NewConfig creates a parser Config.
 func NewConfig() Config {
-	return Config{}
+	return Config{LineNo: 1}
 }

parser/parser.go

@@ -18,7 +18,7 @@ func parseErrorf(format string, a ...interface{}) ParseError {
 
 // Parse parses a source template. It returns an AST root, that can be compiled and evaluated.
 func (c Config) Parse(source string) (ASTNode, error) {
-	tokens := Scan(source, "")
+	tokens := Scan(source, c.Filename, c.LineNo)
 	return c.parseTokens(tokens)
 }
 

parser/scanner.go

@@ -8,12 +8,12 @@ import (
 var tokenMatcher = regexp.MustCompile(`{{\s*(.+?)\s*}}|{%\s*(\w+)(?:\s+((?:[^%]|%[^}])+?))?\s*%}`)
 
 // Scan breaks a string into a sequence of Tokens.
-func Scan(data string, pathname string) []Token {
+func Scan(data string, pathname string, firstLine int) []Token {
 	// TODO error on unterminated {{ and {%
 	// TODO probably an error when a tag contains a {{ or {%, at least outside of a string
 	var (
 		p, pe = 0, len(data)
-		si    = SourceInfo{pathname, 1}
+		si    = SourceInfo{pathname, firstLine}
 		out   = make([]Token, 0)
 	)
 	for _, m := range tokenMatcher.FindAllStringSubmatchIndex(data, -1) {

parser/scanner_test.go

@@ -22,45 +22,46 @@ var scannerCountTests = []struct {
 	{`{{ expr arg }}{{ expr arg }}`, 2},
 }
 
-func TestChunkScanner(t *testing.T) {
-	tokens := Scan("12", "")
+func TestScan(t *testing.T) {
+	scan := func(src string) []Token { return Scan(src, "", 1) }
+	tokens := scan("12")
 	require.NotNil(t, tokens)
 	require.Len(t, tokens, 1)
 	require.Equal(t, TextTokenType, tokens[0].Type)
 	require.Equal(t, "12", tokens[0].Source)
 
-	tokens = Scan("{{obj}}", "")
+	tokens = scan("{{obj}}")
 	require.NotNil(t, tokens)
 	require.Len(t, tokens, 1)
 	require.Equal(t, ObjTokenType, tokens[0].Type)
 	require.Equal(t, "obj", tokens[0].Args)
 
-	tokens = Scan("{{ obj }}", "")
+	tokens = scan("{{ obj }}")
 	require.NotNil(t, tokens)
 	require.Len(t, tokens, 1)
 	require.Equal(t, ObjTokenType, tokens[0].Type)
 	require.Equal(t, "obj", tokens[0].Args)
 
-	tokens = Scan("{%tag args%}", "")
+	tokens = scan("{%tag args%}")
 	require.NotNil(t, tokens)
 	require.Len(t, tokens, 1)
 	require.Equal(t, TagTokenType, tokens[0].Type)
 	require.Equal(t, "tag", tokens[0].Name)
 	require.Equal(t, "args", tokens[0].Args)
 
-	tokens = Scan("{% tag args %}", "")
+	tokens = scan("{% tag args %}")
 	require.NotNil(t, tokens)
 	require.Len(t, tokens, 1)
 	require.Equal(t, TagTokenType, tokens[0].Type)
 	require.Equal(t, "tag", tokens[0].Name)
 	require.Equal(t, "args", tokens[0].Args)
 
-	tokens = Scan("pre{% tag args %}mid{{ object }}post", "")
+	tokens = scan("pre{% tag args %}mid{{ object }}post")
 	require.Equal(t, `[TextTokenType{"pre"} TagTokenType{Tag:"tag", Args:"args"} TextTokenType{"mid"} ObjTokenType{"object"} TextTokenType{"post"}]`, fmt.Sprint(tokens))
 
 	for i, test := range scannerCountTests {
 		t.Run(fmt.Sprintf("%02d", i), func(t *testing.T) {
-			tokens := Scan(test.in, "")
+			tokens := scan(test.in)
 			require.Len(t, tokens, test.len)
 		})
 	}

render/config.go

@@ -7,7 +7,6 @@ import (
 // Config holds configuration information for parsing and rendering.
 type Config struct {
 	parser.Config
-	Filename  string
 	tags      map[string]TagCompiler
 	blockDefs map[string]*blockSyntax
 }

render/node_context.go

@@ -5,6 +5,9 @@ import (
 )
 
 // nodeContext provides the evaluation context for rendering the AST.
+//
+// This type has a clumsy name so that render.Context, in the public API, can
+// have a clean name that doesn't stutter.
 type nodeContext struct {
 	bindings map[string]interface{}
 	config   Config
@@ -18,7 +21,6 @@ func newNodeContext(scope map[string]interface{}, c Config) nodeContext {
 	for k, v := range scope {
 		vars[k] = v
 	}
-	// fmt.Println("new", c.Config)
 	return nodeContext{vars, c}
 }
 

template.go

@@ -13,6 +13,7 @@ type Template interface {
 	// RenderString is a convenience wrapper for Render, that has string input and output.
 	RenderString(Bindings) (string, error)
 	SetSourcePath(string)
+	SetSourceLocation(string, int)
 }
 
 type template struct {
@@ -42,3 +43,8 @@ func (t *template) RenderString(b Bindings) (string, error) {
 func (t *template) SetSourcePath(filename string) {
 	t.config.Filename = filename
 }
+
+func (t *template) SetSourceLocation(filename string, lineNo int) {
+	t.config.Filename = filename
+	t.config.LineNo = lineNo
+}