Split package render->parser

2024-11-30 06:08:57 +01:00 · 2017-07-07 05:41:37 -04:00 · 2017-07-07 05:41:37 -04:00 · 903acb8d2e
commit 903acb8d2e
parent 18e2540b3a
26 changed files with 174 additions and 126 deletions
--- a/README.md
+++ b/README.md
@ -1,9 +1,6 @@
 # Go Liquid Template Parser

-[![Build Status](https://travis-ci.org/osteele/liquid.svg?branch=master)](https://travis-ci.org/osteele/liquid)
-[![Go Report Card](https://goreportcard.com/badge/github.com/osteele/liquid)](https://goreportcard.com/report/github.com/osteele/liquid)
-[![GoDoc](https://godoc.org/github.com/osteele/liquid?status.svg)](http://godoc.org/github.com/osteele/liquid)
-[![Coverage Status](https://coveralls.io/repos/github/osteele/liquid/badge.svg?branch=master)](https://coveralls.io/github/osteele/liquid?branch=master)
+ [![][travis-svg]][travis-url] [![][coveralls-svg]][coveralls-url] [![][go-report-card-svg]][go-report-card-url] [![][godoc-svg]][godoc-url] [![][license-svg]][license-url]

 > “Any sufficiently complicated C or Fortran program contains an ad-hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp.” – Philip Greenspun

@ -127,3 +124,18 @@ The [original Liquid engine](https://shopify.github.io/liquid), of course, for t
 ## License

 MIT License
+
+[coveralls-url]: https://coveralls.io/r/osteele/liquid?branch=master
+[coveralls-svg]: https://img.shields.io/coveralls/osteele/liquid.svg?branch=master
+
+[godoc-url]: https://godoc.org/github.com/osteele/liquid
+[godoc-svg]: https://godoc.org/github.com/osteele/liquid?status.svg
+
+[license-url]: https://github.com/osteele/liquid/blob/master/LICENSE
+[license-svg]: https://img.shields.io/badge/license-MIT-blue.svg
+
+[go-report-card-url]: https://goreportcard.com/report/github.com/osteele/liquid
+[go-report-card-svg]: https://goreportcard.com/badge/github.com/osteele/liquid
+
+[travis-url]: https://travis-ci.org/osteele/liquid
+[travis-svg]: https://img.shields.io/travis/osteele/liquid.svg?branch=master
--- a/engine.go
+++ b/engine.go
@ -13,7 +13,7 @@ type engine struct{ settings render.Config }
 // NewEngine returns a new template engine.
 func NewEngine() Engine {
 	e := engine{render.NewConfig()}
-	filters.AddStandardFilters(e.settings.Config)
+	filters.AddStandardFilters(&e.settings.Config.Config)
 	tags.AddStandardTags(e.settings)
 	return e
 }
@ -57,7 +57,7 @@ func (e engine) ParseTemplate(text []byte) (Template, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &template{ast, e.settings}, nil
+	return &template{ast, &e.settings}, nil
 }

 // ParseAndRender is in the Engine interface.
--- a/evaluator/call.go
+++ b/evaluator/call.go
@ -1,7 +1,6 @@
 package evaluator

 import (
-	"fmt"
 	"reflect"
 )

@ -15,7 +14,6 @@ func Call(fn reflect.Value, args []interface{}) (interface{}, error) {
 	if len(outs) > 1 && outs[1].Interface() != nil {
 		switch e := outs[1].Interface().(type) {
 		case error:
-			fmt.Println("error")
 			return nil, e
 		default:
 			panic(e)
--- a/expression/filters.go
+++ b/expression/filters.go
@ -44,6 +44,9 @@ func (d *filterDictionary) AddFilter(name string, fn interface{}) {
 		// case rf.Type().Out(1).Implements(…):
 		// 	panic(typeError("a filter's second output must be type error"))
 	}
+	if len(d.filters) == 0 {
+		d.filters = make(map[string]interface{})
+	}
 	d.filters[name] = fn
 }

--- a/expression/filters_test.go
+++ b/expression/filters_test.go
@ -9,7 +9,6 @@ import (

 func TestContext_runFilter(t *testing.T) {
 	cfg := NewConfig()
-	ctx := NewContext(map[string]interface{}{"x": 10}, cfg)
 	constant := func(value interface{}) valueFn {
 		return func(Context) interface{} { return value }
 	}
@ -19,6 +18,7 @@ func TestContext_runFilter(t *testing.T) {
 	cfg.AddFilter("f1", func(s string) string {
 		return "<" + s + ">"
 	})
+	ctx := NewContext(map[string]interface{}{"x": 10}, cfg)
 	out := ctx.ApplyFilter("f1", receiver, []valueFn{})
 	require.Equal(t, "<self>", out)

@ -26,6 +26,7 @@ func TestContext_runFilter(t *testing.T) {
 	cfg.AddFilter("with_arg", func(a, b string) string {
 		return fmt.Sprintf("(%s, %s)", a, b)
 	})
+	ctx = NewContext(map[string]interface{}{"x": 10}, cfg)
 	out = ctx.ApplyFilter("with_arg", receiver, []valueFn{constant("arg")})
 	require.Equal(t, "(self, arg)", out)

@ -43,6 +44,7 @@ func TestContext_runFilter(t *testing.T) {
 		}
 		return fmt.Sprintf("(%v, %v)", a, value), nil
 	})
+	ctx = NewContext(map[string]interface{}{"x": 10}, cfg)
 	out = ctx.ApplyFilter("closure", receiver, []valueFn{constant("x |add: y")})
 	require.Equal(t, "(self, 11)", out)
 }
--- a/filters/filter_test.go
+++ b/filters/filter_test.go
@ -161,7 +161,7 @@ var filterTestBindings = map[string]interface{}{

 func TestFilters(t *testing.T) {
 	settings := expression.NewConfig()
-	AddStandardFilters(settings)
+	AddStandardFilters(&settings)
 	context := expression.NewContext(filterTestBindings, settings)

 	for i, test := range filterTests {
--- a/filters/filters.go
+++ b/filters/filters.go
@ -19,9 +19,9 @@ import (
 )

 // AddStandardFilters defines the standard Liquid filters.
-func AddStandardFilters(settings expression.Config) { // nolint: gocyclo
+func AddStandardFilters(cfg *expression.Config) { // nolint: gocyclo
 	// values
-	settings.AddFilter("default", func(value, defaultValue interface{}) interface{} {
+	cfg.AddFilter("default", func(value, defaultValue interface{}) interface{} {
 		if value == nil || value == false || evaluator.IsEmpty(value) {
 			value = defaultValue
 		}
@ -29,7 +29,7 @@ func AddStandardFilters(settings expression.Config) { // nolint: gocyclo
 	})

 	// dates
-	settings.AddFilter("date", func(t time.Time, format interface{}) (string, error) {
+	cfg.AddFilter("date", func(t time.Time, format interface{}) (string, error) {
 		form, ok := format.(string)
 		if !ok {
 			form = "%a, %b %d, %y"
@ -40,7 +40,7 @@ func AddStandardFilters(settings expression.Config) { // nolint: gocyclo
 	})

 	// arrays
-	settings.AddFilter("compact", func(array []interface{}) interface{} {
+	cfg.AddFilter("compact", func(array []interface{}) interface{} {
 		out := []interface{}{}
 		for _, item := range array {
 			if item != nil {
@ -49,25 +49,25 @@ func AddStandardFilters(settings expression.Config) { // nolint: gocyclo
 		}
 		return out
 	})
-	settings.AddFilter("join", joinFilter)
-	settings.AddFilter("map", func(array []map[string]interface{}, key string) interface{} {
+	cfg.AddFilter("join", joinFilter)
+	cfg.AddFilter("map", func(array []map[string]interface{}, key string) interface{} {
 		out := []interface{}{}
 		for _, obj := range array {
 			out = append(out, obj[key])
 		}
 		return out
 	})
-	settings.AddFilter("reverse", reverseFilter)
-	settings.AddFilter("sort", sortFilter)
+	cfg.AddFilter("reverse", reverseFilter)
+	cfg.AddFilter("sort", sortFilter)
 	// https://shopify.github.io/liquid/ does not demonstrate first and last as filters,
 	// but https://help.shopify.com/themes/liquid/filters/array-filters does
-	settings.AddFilter("first", func(array []interface{}) interface{} {
+	cfg.AddFilter("first", func(array []interface{}) interface{} {
 		if len(array) == 0 {
 			return nil
 		}
 		return array[0]
 	})
-	settings.AddFilter("last", func(array []interface{}) interface{} {
+	cfg.AddFilter("last", func(array []interface{}) interface{} {
 		if len(array) == 0 {
 			return nil
 		}
@ -75,20 +75,20 @@ func AddStandardFilters(settings expression.Config) { // nolint: gocyclo
 	})

 	// numbers
-	settings.AddFilter("abs", math.Abs)
-	settings.AddFilter("ceil", math.Ceil)
-	settings.AddFilter("floor", math.Floor)
-	settings.AddFilter("modulo", math.Mod)
-	settings.AddFilter("minus", func(a, b float64) float64 {
+	cfg.AddFilter("abs", math.Abs)
+	cfg.AddFilter("ceil", math.Ceil)
+	cfg.AddFilter("floor", math.Floor)
+	cfg.AddFilter("modulo", math.Mod)
+	cfg.AddFilter("minus", func(a, b float64) float64 {
 		return a - b
 	})
-	settings.AddFilter("plus", func(a, b float64) float64 {
+	cfg.AddFilter("plus", func(a, b float64) float64 {
 		return a + b
 	})
-	settings.AddFilter("times", func(a, b float64) float64 {
+	cfg.AddFilter("times", func(a, b float64) float64 {
 		return a * b
 	})
-	settings.AddFilter("divided_by", func(a float64, b interface{}) interface{} {
+	cfg.AddFilter("divided_by", func(a float64, b interface{}) interface{} {
 		switch bt := b.(type) {
 		case int, int16, int32, int64:
 			return int(a) / bt.(int)
@ -98,7 +98,7 @@ func AddStandardFilters(settings expression.Config) { // nolint: gocyclo
 			return nil
 		}
 	})
-	settings.AddFilter("round", func(n float64, places interface{}) float64 {
+	cfg.AddFilter("round", func(n float64, places interface{}) float64 {
 		pl, ok := places.(int)
 		if !ok {
 			pl = 0
@ -108,45 +108,45 @@ func AddStandardFilters(settings expression.Config) { // nolint: gocyclo
 	})

 	// sequences
-	settings.AddFilter("size", evaluator.Length)
+	cfg.AddFilter("size", evaluator.Length)

 	// strings
-	settings.AddFilter("append", func(s, suffix string) string {
+	cfg.AddFilter("append", func(s, suffix string) string {
 		return s + suffix
 	})
-	settings.AddFilter("capitalize", func(s, suffix string) string {
+	cfg.AddFilter("capitalize", func(s, suffix string) string {
 		if len(s) < 1 {
 			return s
 		}
 		return strings.ToUpper(s[:1]) + s[1:]
 	})
-	settings.AddFilter("downcase", func(s, suffix string) string {
+	cfg.AddFilter("downcase", func(s, suffix string) string {
 		return strings.ToLower(s)
 	})
-	settings.AddFilter("escape", html.EscapeString)
-	settings.AddFilter("escape_once", func(s, suffix string) string {
+	cfg.AddFilter("escape", html.EscapeString)
+	cfg.AddFilter("escape_once", func(s, suffix string) string {
 		return html.EscapeString(html.UnescapeString(s))
 	})
 	// TODO test case for this
-	settings.AddFilter("newline_to_br", func(s string) string {
+	cfg.AddFilter("newline_to_br", func(s string) string {
 		return strings.Replace(s, "\n", "<br />", -1)
 	})
-	settings.AddFilter("prepend", func(s, prefix string) string {
+	cfg.AddFilter("prepend", func(s, prefix string) string {
 		return prefix + s
 	})
-	settings.AddFilter("remove", func(s, old string) string {
+	cfg.AddFilter("remove", func(s, old string) string {
 		return strings.Replace(s, old, "", -1)
 	})
-	settings.AddFilter("remove_first", func(s, old string) string {
+	cfg.AddFilter("remove_first", func(s, old string) string {
 		return strings.Replace(s, old, "", 1)
 	})
-	settings.AddFilter("replace", func(s, old, new string) string {
+	cfg.AddFilter("replace", func(s, old, new string) string {
 		return strings.Replace(s, old, new, -1)
 	})
-	settings.AddFilter("replace_first", func(s, old, new string) string {
+	cfg.AddFilter("replace_first", func(s, old, new string) string {
 		return strings.Replace(s, old, new, 1)
 	})
-	settings.AddFilter("slice", func(s string, start int, length interface{}) string {
+	cfg.AddFilter("slice", func(s string, start int, length interface{}) string {
 		// runes aren't bytes; don't use slice
 		n, ok := length.(int)
 		if !ok {
@ -158,23 +158,23 @@ func AddStandardFilters(settings expression.Config) { // nolint: gocyclo
 		p := regexp.MustCompile(fmt.Sprintf(`^.{%d}(.{0,%d}).*$`, start, n))
 		return p.ReplaceAllString(s, "$1")
 	})
-	settings.AddFilter("split", splitFilter)
-	settings.AddFilter("strip_html", func(s string) string {
+	cfg.AddFilter("split", splitFilter)
+	cfg.AddFilter("strip_html", func(s string) string {
 		// TODO this probably isn't sufficient
 		return regexp.MustCompile(`<.*?>`).ReplaceAllString(s, "")
 	})
 	// TODO test case for this
-	settings.AddFilter("strip_newlines", func(s string) string {
+	cfg.AddFilter("strip_newlines", func(s string) string {
 		return strings.Replace(s, "\n", "", -1)
 	})
-	settings.AddFilter("strip", strings.TrimSpace)
-	settings.AddFilter("lstrip", func(s string) string {
+	cfg.AddFilter("strip", strings.TrimSpace)
+	cfg.AddFilter("lstrip", func(s string) string {
 		return strings.TrimLeftFunc(s, unicode.IsSpace)
 	})
-	settings.AddFilter("rstrip", func(s string) string {
+	cfg.AddFilter("rstrip", func(s string) string {
 		return strings.TrimRightFunc(s, unicode.IsSpace)
 	})
-	settings.AddFilter("truncate", func(s string, n int, ellipsis interface{}) string {
+	cfg.AddFilter("truncate", func(s string, n int, ellipsis interface{}) string {
 		// runes aren't bytes; don't use slice
 		el, ok := ellipsis.(string)
 		if !ok {
@ -183,20 +183,20 @@ func AddStandardFilters(settings expression.Config) { // nolint: gocyclo
 		p := regexp.MustCompile(fmt.Sprintf(`^(.{%d})..{%d,}`, n-len(el), len(el)))
 		return p.ReplaceAllString(s, `$1`+el)
 	})
-	settings.AddFilter("upcase", func(s, suffix string) string {
+	cfg.AddFilter("upcase", func(s, suffix string) string {
 		return strings.ToUpper(s)
 	})

 	// debugging extensions
 	// inspect is from Jekyll
-	settings.AddFilter("inspect", func(value interface{}) string {
+	cfg.AddFilter("inspect", func(value interface{}) string {
 		s, err := json.Marshal(value)
 		if err != nil {
 			return fmt.Sprintf("%#v", value)
 		}
 		return string(s)
 	})
-	settings.AddFilter("type", func(value interface{}) string {
+	cfg.AddFilter("type", func(value interface{}) string {
 		return reflect.TypeOf(value).String()
 	})
 }
--- a/liquid.go
+++ b/liquid.go
@ -3,7 +3,7 @@ Package liquid is a pure Go implementation of Shopify Liquid templates, for use

 See the project README https://github.com/osteele/liquid for additional information and implementation status.

-Note that the API for this package is not frozen. It is *especiallY* likely that subpackage APIs will
+Note that the API for this package is not frozen. It is *especially* likely that subpackage APIs will
 change drastically. Don't use anything except from a subpackage except render.Context.
 */
 package liquid
@ -11,6 +11,7 @@ package liquid
 import (
 	"github.com/osteele/liquid/evaluator"
 	"github.com/osteele/liquid/expression"
+	"github.com/osteele/liquid/parser"
 	"github.com/osteele/liquid/render"
 )

@ -71,9 +72,9 @@ func IsTemplateError(err error) bool {
 		return true
 	case expression.ParseError:
 		return true
-	case render.CompilationError:
+	case parser.ParseError:
 		return true
-	case render.ParseError:
+	case render.CompilationError:
 		return true
 	case render.Error:
 		return true
--- a/liquid_test.go
+++ b/liquid_test.go
@ -1,7 +1,6 @@
 package liquid

 import (
-	"fmt"
 	"testing"

 	"github.com/stretchr/testify/require"
@ -9,7 +8,6 @@ import (

 func TestIsTemplateError(t *testing.T) {
 	_, err := NewEngine().ParseAndRenderString("{{ syntax error }}", emptyBindings)
-	fmt.Printf("%T", err)
 	require.True(t, IsTemplateError(err))
 	_, err = NewEngine().ParseAndRenderString("{% if %}", emptyBindings)
 	require.True(t, IsTemplateError(err))
--- a/parser/ast.go
+++ b/parser/ast.go
@ -1,4 +1,4 @@
-package render
+package parser

 import (
 	"github.com/osteele/liquid/expression"
@ -17,7 +17,7 @@ type ASTBlock struct {

 // ASTRaw holds the text between the start and end of a raw tag.
 type ASTRaw struct {
-	slices []string
+	Slices []string
 }

 // ASTTag is a tag.
@ -33,7 +33,7 @@ type ASTText struct {
 // ASTObject is an {{ object }} object.
 type ASTObject struct {
 	Chunk
-	expr expression.Expression
+	Expr expression.Expression
 }

 // ASTSeq is a sequence of nodes.
--- a/parser/chunk.go
+++ b/parser/chunk.go
@ -1,4 +1,4 @@
-package render
+package parser

 import "fmt"

--- a/parser/chunktype_string.go
+++ b/parser/chunktype_string.go
@ -1,6 +1,6 @@
 // Code generated by "stringer -type=ChunkType"; DO NOT EDIT.

-package render
+package parser

 import "fmt"

--- a/parser/config.go
+++ b/parser/config.go
@ -0,0 +1,15 @@
+package parser
+
+import "github.com/osteele/liquid/expression"
+
+// // Config holds configuration information for parsing and rendering.
+type Config struct {
+	expression.Config
+	// 	Filename  string
+	Grammar Grammar
+}
+
+// NewConfig creates a new Settings.
+func NewConfig() Config {
+	return Config{Config: expression.NewConfig()}
+}
--- a/parser/grammar.go
+++ b/parser/grammar.go
@ -1,4 +1,4 @@
-package render
+package parser

 // Grammar supplies the parser with syntax information about blocks.
 type Grammar interface {
@ -18,4 +18,4 @@ type BlockSyntax interface {
 }

 // Grammar returns a configuration's grammar.
-func (c *Config) Grammar() Grammar { return c }
+// func (c *Config) Grammar() Grammar { return c }
--- a/parser/parser.go
+++ b/parser/parser.go
@ -1,4 +1,4 @@
-package render
+package parser

 import (
 	"fmt"
@ -31,7 +31,7 @@ func (c Config) parseChunks(chunks []Chunk) (ASTNode, error) { // nolint: gocycl
 		ap     *[]ASTNode
 	}
 	var (
-		g         = c.Grammar()
+		g         = c.Grammar
 		root      = &ASTSeq{}      // root of AST; will be returned
 		ap        = &root.Children // newly-constructed nodes are appended here
 		sd        BlockSyntax      // current block syntax definition
@ -54,7 +54,7 @@ func (c Config) parseChunks(chunks []Chunk) (ASTNode, error) { // nolint: gocycl
 			if ch.Type == TagChunkType && ch.Name == "endraw" {
 				inRaw = false
 			} else {
-				rawTag.slices = append(rawTag.slices, ch.Source)
+				rawTag.Slices = append(rawTag.Slices, ch.Source)
 			}
 		case ch.Type == ObjChunkType:
 			expr, err := expression.Parse(ch.Args)
@ -99,7 +99,7 @@ func (c Config) parseChunks(chunks []Chunk) (ASTNode, error) { // nolint: gocycl
 					}
 					pop()
 				default:
-					panic("unexpected block type")
+					panic(fmt.Errorf("block type %q", ch.Name))
 				}
 			} else {
 				*ap = append(*ap, &ASTTag{ch})
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@ -1,21 +1,33 @@
-package render
+package parser

 import (
 	"fmt"
+	"strings"
 	"testing"

 	"github.com/stretchr/testify/require"
 )

-func addParserTestTags(s Config) {
-	s.AddBlock("case").Branch("when")
-	s.AddBlock("comment")
-	s.AddBlock("for").Governs([]string{"break"})
-	s.AddBlock("if").Branch("else").Branch("elsif")
-	s.AddBlock("unless").SameSyntaxAs("if")
-	s.AddBlock("raw")
+type grammarFake struct{}
+type blockSyntaxFake string
+
+func (g grammarFake) BlockSyntax(w string) (BlockSyntax, bool) {
+	return blockSyntaxFake(w), true
 }

+func (g blockSyntaxFake) IsBlock() bool { return true }
+func (g blockSyntaxFake) CanHaveParent(p BlockSyntax) bool {
+	return string(g) == "end"+p.TagName() || (g == "else" && p.TagName() == "if")
+}
+func (g blockSyntaxFake) IsBlockEnd() bool { return strings.HasPrefix(string(g), "end") }
+func (g blockSyntaxFake) IsBlockStart() bool {
+	return g == "for" || g == "if" || g == "unless"
+}
+func (g blockSyntaxFake) IsBranch() bool       { return g == "else" }
+func (g blockSyntaxFake) ParentTags() []string { return []string{"unless"} }
+func (g blockSyntaxFake) RequiresParent() bool { return g == "else" || g.IsBlockEnd() }
+func (g blockSyntaxFake) TagName() string      { return string(g) }
+
 var parseErrorTests = []struct{ in, expected string }{
 	{"{% if test %}", "unterminated if block"},
 	{"{% if test %}{% endunless %}", "not inside unless"},
@ -28,7 +40,7 @@ var parserTests = []struct{ in string }{
 	{`{% for item in list %}{% endfor %}`},
 	{`{% if test %}{% else %}{% endif %}`},
 	{`{% if test %}{% if test %}{% endif %}{% endif %}`},
-	{`{% unless test %}{% else %}{% endunless %}`},
+	{`{% unless test %}{% endunless %}`},
 	{`{% for item in list %}{% if test %}{% else %}{% endif %}{% endfor %}`},
 	{`{% if true %}{% raw %}{% endraw %}{% endif %}`},

@ -37,11 +49,10 @@ var parserTests = []struct{ in string }{
 }

 func TestParseErrors(t *testing.T) {
-	settings := NewConfig()
-	addParserTestTags(settings)
+	cfg := Config{Grammar:grammarFake{}}
 	for i, test := range parseErrorTests {
 		t.Run(fmt.Sprintf("%02d", i+1), func(t *testing.T) {
-			_, err := settings.Parse(test.in)
+			_, err := cfg.Parse(test.in)
 			require.Errorf(t, err, test.in)
 			require.Containsf(t, err.Error(), test.expected, test.in)
 		})
@ -49,11 +60,10 @@ func TestParseErrors(t *testing.T) {
 }

 func TestParser(t *testing.T) {
-	settings := NewConfig()
-	addParserTestTags(settings)
+	cfg := Config{Grammar:grammarFake{}}
 	for i, test := range parserTests {
 		t.Run(fmt.Sprintf("%02d", i+1), func(t *testing.T) {
-			_, err := settings.Parse(test.in)
+			_, err := cfg.Parse(test.in)
 			require.NoError(t, err, test.in)
 		})
 	}
--- a/parser/scanner.go
+++ b/parser/scanner.go
@ -1,4 +1,4 @@
-package render
+package parser

 import (
 	"regexp"
--- a/parser/scanner_test.go
+++ b/parser/scanner_test.go
@ -1,4 +1,4 @@
-package render
+package parser

 import (
 	"fmt"
--- a/render/blocks.go
+++ b/render/blocks.go
@ -3,6 +3,8 @@ package render
 import (
 	"fmt"
 	"io"
+
+	"github.com/osteele/liquid/parser"
 )

 // BlockCompiler builds a renderer for the tag instance.
@ -17,7 +19,7 @@ type blockSyntax struct {
 	parser                BlockCompiler
 }

-func (c *blockSyntax) CanHaveParent(parent BlockSyntax) bool {
+func (c *blockSyntax) CanHaveParent(parent parser.BlockSyntax) bool {
 	if parent == nil {
 		return false
 	}
@ -52,7 +54,7 @@ func (c Config) findBlockDef(name string) (*blockSyntax, bool) {
 }

 // BlockSyntax is part of the Grammar interface.
-func (c Config) BlockSyntax(name string) (BlockSyntax, bool) {
+func (c Config) BlockSyntax(name string) (parser.BlockSyntax, bool) {
 	ct, found := c.blockDefs[name]
 	return ct, found
 }
--- a/render/compiler.go
+++ b/render/compiler.go
@ -2,6 +2,8 @@ package render

 import (
 	"fmt"
+
+	"github.com/osteele/liquid/parser"
 )

 // A CompilationError is a parse error during template compilation.
@ -14,7 +16,7 @@ func compilationErrorf(format string, a ...interface{}) CompilationError {
 }

 // Compile parses a source template. It returns an AST root, that can be evaluated.
-func (c Config) Compile(source string) (ASTNode, error) {
+func (c Config) Compile(source string) (parser.ASTNode, error) {
 	root, err := c.Parse(source)
 	if err != nil {
 		return nil, err
@ -23,9 +25,9 @@ func (c Config) Compile(source string) (ASTNode, error) {
 }

 // nolint: gocyclo
-func (c Config) compileNode(n ASTNode) (Node, error) {
+func (c Config) compileNode(n parser.ASTNode) (Node, error) {
 	switch n := n.(type) {
-	case *ASTBlock:
+	case *parser.ASTBlock:
 		body, err := c.compileNodes(n.Body)
 		if err != nil {
 			return nil, err
@ -52,15 +54,15 @@ func (c Config) compileNode(n ASTNode) (Node, error) {
 			node.renderer = r
 		}
 		return &node, nil
-	case *ASTRaw:
-		return &RawNode{n.slices}, nil
-	case *ASTSeq:
+	case *parser.ASTRaw:
+		return &RawNode{n.Slices}, nil
+	case *parser.ASTSeq:
 		children, err := c.compileNodes(n.Children)
 		if err != nil {
 			return nil, err
 		}
 		return &SeqNode{children}, nil
-	case *ASTTag:
+	case *parser.ASTTag:
 		if td, ok := c.FindTagDefinition(n.Name); ok {
 			f, err := td(n.Args)
 			if err != nil {
@ -69,16 +71,16 @@ func (c Config) compileNode(n ASTNode) (Node, error) {
 			return &TagNode{n.Chunk, f}, nil
 		}
 		return nil, compilationErrorf("unknown tag: %s", n.Name)
-	case *ASTText:
+	case *parser.ASTText:
 		return &TextNode{n.Chunk}, nil
-	case *ASTObject:
-		return &ObjectNode{n.Chunk, n.expr}, nil
+	case *parser.ASTObject:
+		return &ObjectNode{n.Chunk, n.Expr}, nil
 	default:
 		panic(fmt.Errorf("un-compilable node type %T", n))
 	}
 }

-func (c Config) compileBlocks(blocks []*ASTBlock) ([]*BlockNode, error) {
+func (c Config) compileBlocks(blocks []*parser.ASTBlock) ([]*BlockNode, error) {
 	out := make([]*BlockNode, 0, len(blocks))
 	for _, child := range blocks {
 		compiled, err := c.compileNode(child)
@ -90,7 +92,7 @@ func (c Config) compileBlocks(blocks []*ASTBlock) ([]*BlockNode, error) {
 	return out, nil
 }

-func (c Config) compileNodes(nodes []ASTNode) ([]Node, error) {
+func (c Config) compileNodes(nodes []parser.ASTNode) ([]Node, error) {
 	out := make([]Node, 0, len(nodes))
 	for _, child := range nodes {
 		compiled, err := c.compileNode(child)
--- a/render/config.go
+++ b/render/config.go
@ -1,11 +1,12 @@
 package render

-import "github.com/osteele/liquid/expression"
+import (
+	"github.com/osteele/liquid/parser"
+)

 // Config holds configuration information for parsing and rendering.
 type Config struct {
-	// ExpressionConfig expression.Config
-	expression.Config
+	parser.Config
 	Filename  string
 	tags      map[string]TagCompiler
 	blockDefs map[string]*blockSyntax
@ -13,15 +14,16 @@ type Config struct {

 // NewConfig creates a new Settings.
 func NewConfig() Config {
-	s := Config{
-		Config:    expression.NewConfig(),
+	c := Config{
+		// Config:    parser.NewConfig(),
 		tags:      map[string]TagCompiler{},
 		blockDefs: map[string]*blockSyntax{},
 	}
-	return s
+	c.Grammar = c
+	return c
 }

 // AddFilter adds a filter to settings.
-func (s Config) AddFilter(name string, fn interface{}) {
-	s.Config.AddFilter(name, fn)
-}
+// func (s Config) AddFilter(name string, fn interface{}) {
+// 	s.Config.AddFilter(name, fn)
+// }
--- a/render/context.go
+++ b/render/context.go
@ -55,7 +55,7 @@ func (c renderContext) EvaluateString(source string) (out interface{}, err error
 			}
 		}
 	}()
-	return expression.EvaluateString(source, expression.NewContext(c.ctx.bindings, c.ctx.config.Config))
+	return expression.EvaluateString(source, expression.NewContext(c.ctx.bindings, c.ctx.config.Config.Config))
 }

 // Get gets a variable value within an evaluation context.
--- a/render/node_context.go
+++ b/render/node_context.go
@ -11,14 +11,15 @@ type nodeContext struct {
 }

 // newNodeContext creates a new evaluation context.
-func newNodeContext(scope map[string]interface{}, s Config) nodeContext {
+func newNodeContext(scope map[string]interface{}, c Config) nodeContext {
 	// The assign tag modifies the scope, so make a copy first.
 	// TODO this isn't really the right place for this.
 	vars := map[string]interface{}{}
 	for k, v := range scope {
 		vars[k] = v
 	}
-	return nodeContext{vars, s}
+	// fmt.Println("new", c.Config)
+	return nodeContext{vars, c}
 }

 // Clone makes a copy of a context, with copied bindings.
@ -43,5 +44,5 @@ func (c nodeContext) Evaluate(expr expression.Expression) (out interface{}, err
 			}
 		}
 	}()
-	return expr.Evaluate(expression.NewContext(c.bindings, c.config.Config))
+	return expr.Evaluate(expression.NewContext(c.bindings, c.config.Config.Config))
 }
--- a/render/nodes.go
+++ b/render/nodes.go
@ -4,6 +4,7 @@ import (
 	"io"

 	"github.com/osteele/liquid/expression"
+	"github.com/osteele/liquid/parser"
 )

 // Node is a node of the render tree.
@ -12,7 +13,7 @@ type Node interface {

 // BlockNode represents a {% tag %}…{% endtag %}.
 type BlockNode struct {
-	Chunk
+	parser.Chunk
 	renderer func(io.Writer, Context) error
 	Body     []Node
 	Branches []*BlockNode
@ -25,18 +26,18 @@ type RawNode struct {

 // TagNode renders itself via a render function that is created during parsing.
 type TagNode struct {
-	Chunk
+	parser.Chunk
 	renderer func(io.Writer, Context) error
 }

 // TextNode is a text chunk, that is rendered verbatim.
 type TextNode struct {
-	Chunk
+	parser.Chunk
 }

 // ObjectNode is an {{ object }} object.
 type ObjectNode struct {
-	Chunk
+	parser.Chunk
 	expr expression.Expression
 }

--- a/render/render.go
+++ b/render/render.go
@ -20,8 +20,9 @@ func Errorf(format string, a ...interface{}) Error {
 }

 // Render renders the render tree.
-func Render(node Node, w io.Writer, b map[string]interface{}, c Config) error {
-	return renderNode(node, w, newNodeContext(b, c))
+func Render(node Node, w io.Writer, vars map[string]interface{}, c Config) error {
+	// fmt.Println("render", c)
+	return renderNode(node, w, newNodeContext(vars, c))
 }

 func renderNode(node Node, w io.Writer, ctx nodeContext) error { // nolint: gocyclo
@ -31,11 +32,11 @@ func renderNode(node Node, w io.Writer, ctx nodeContext) error { // nolint: gocy
 	case *BlockNode:
 		cd, ok := ctx.config.findBlockDef(n.Name)
 		if !ok || cd.parser == nil {
-			return parseErrorf("unknown tag: %s", n.Name)
+			return Errorf("unknown tag: %s", n.Name)
 		}
 		renderer := n.renderer
 		if renderer == nil {
-			panic(parseErrorf("unset renderer for %v", n))
+			panic(Errorf("unset renderer for %v", n))
 		}
 		return renderer(w, renderContext{ctx, nil, n})
 	case *RawNode:
@ -48,7 +49,7 @@ func renderNode(node Node, w io.Writer, ctx nodeContext) error { // nolint: gocy
 	case *ObjectNode:
 		value, err := ctx.Evaluate(n.expr)
 		if err != nil {
-			return parseErrorf("%s in %s", err, n.Source)
+			return Errorf("%s in %s", err, n.Source)
 		}
 		return writeObject(value, w)
 	case *SeqNode:
@ -61,7 +62,7 @@ func renderNode(node Node, w io.Writer, ctx nodeContext) error { // nolint: gocy
 		_, err := w.Write([]byte(n.Source))
 		return err
 	default:
-		panic(parseErrorf("unknown node type %T", node))
+		panic(Errorf("unknown node type %T", node))
 	}
 	return nil
 }
--- a/template.go
+++ b/template.go
@ -7,14 +7,14 @@ import (
 )

 type template struct {
-	ast    render.ASTNode
-	config render.Config
+	root   render.Node
+	config *render.Config
 }

 // Render executes the template within the bindings environment.
-func (t *template) Render(b Bindings) ([]byte, error) {
+func (t *template) Render(vars Bindings) ([]byte, error) {
 	buf := new(bytes.Buffer)
-	err := render.Render(t.ast, buf, b, t.config)
+	err := render.Render(t.root, buf, vars, *t.config)
 	if err != nil {
 		return nil, err
 	}