Revert whitespace trimming

This commit reverts whitespace trimming after it was reported in
issue #40 that it breaks some use cases.

Reverted commits:

- eb5dd3e
- e79bb8c
- 6f55900
- 6d69dcf
- 438bb0a

Author: benbjohnson

README.md

@@ -152,12 +152,6 @@ The `<%= %>` block will print your text as escaped HTML, however, sometimes you
 To do this, simply wrap your Go expression with `<%==` and `%>` tags.
 
 
-#### Trim Space
-
-The `<% %>` blocks can be optionally adorned with a `-` on one or both sides to trigger trimming of whitespace on that side.
-For example `<%-= r.Name %>` will trim whitespace before the print block, but not after it.
-
-
 ### Components
 
 Simple code and print tags work well for simple templates but it can be difficult to make reusable functionality.

ego.go

@@ -10,7 +10,6 @@ import (
 	"io"
 	"sort"
 	"strings"
-	"unicode"
 )
 
 // Template represents an entire Ego template.
@@ -114,8 +113,7 @@ func writeBlocksTo(buf *bytes.Buffer, blks []Block) {
 // Normalize joins together adjacent text blocks.
 func normalizeBlocks(a []Block) []Block {
 	a = joinAdjacentTextBlocks(a)
-	a = trimLeftRight(a)
-	a = trimEmptyTextBlocks(a)
+	a = trimTrailingEmptyTextBlocks(a)
 	return a
 }
 
@@ -144,33 +142,18 @@ func joinAdjacentTextBlocks(a []Block) []Block {
 	return other
 }
 
-func trimLeftRight(a []Block) []Block {
-	for i, blk := range a {
-		trimLeft, trimRight := blk.trim()
-		if trimLeft && i > 1 {
-			if textBlock, ok := a[i-1].(*TextBlock); ok {
-				textBlock.Content = strings.TrimRightFunc(textBlock.Content, unicode.IsSpace)
-			}
-		}
-		if trimRight && i+1 < len(a) {
-			if textBlock, ok := a[i+1].(*TextBlock); ok {
-				textBlock.Content = strings.TrimLeftFunc(textBlock.Content, unicode.IsSpace)
-			}
+func trimTrailingEmptyTextBlocks(a []Block) []Block {
+	for len(a) > 0 {
+		blk, ok := a[len(a)-1].(*TextBlock)
+		if !ok || strings.TrimSpace(blk.Content) != "" {
+			break
 		}
+		a[len(a)-1] = nil
+		a = a[:len(a)-1]
 	}
 	return a
 }
 
-func trimEmptyTextBlocks(a []Block) []Block {
-	b := make([]Block, 0, len(a))
-	for _, blk := range a {
-		if tb, ok := blk.(*TextBlock); !ok || strings.TrimSpace(tb.Content) != "" {
-			b = append(b, blk)
-		}
-	}
-	return b
-}
-
 func injectImports(f *ast.File) {
 	names := []string{`"fmt"`, `"html"`, `"io"`, `"context"`}
 
@@ -249,7 +232,6 @@ func removeImportSpecs(decl *ast.GenDecl, names []string) {
 // Block represents an element of the template.
 type Block interface {
 	block()
-	trim() (bool, bool)
 }
 
 func (*TextBlock) block()           {}
@@ -261,15 +243,6 @@ func (*ComponentEndBlock) block()   {}
 func (*AttrStartBlock) block()      {}
 func (*AttrEndBlock) block()        {}
 
-func (*TextBlock) trim() (bool, bool)           { return false, false }
-func (b *CodeBlock) trim() (bool, bool)         { return b.TrimLeft, b.TrimRight }
-func (b *PrintBlock) trim() (bool, bool)        { return b.TrimLeft, b.TrimRight }
-func (b *RawPrintBlock) trim() (bool, bool)     { return b.TrimLeft, b.TrimRight }
-func (*ComponentStartBlock) trim() (bool, bool) { return false, false }
-func (*ComponentEndBlock) trim() (bool, bool)   { return false, false }
-func (*AttrStartBlock) trim() (bool, bool)      { return false, false }
-func (*AttrEndBlock) trim() (bool, bool)        { return false, false }
-
 // TextBlock represents a UTF-8 encoded block of text that is written to the writer as-is.
 type TextBlock struct {
 	Pos     Pos
@@ -278,26 +251,20 @@ type TextBlock struct {
 
 // CodeBlock represents a Go code block that is printed as-is to the template.
 type CodeBlock struct {
-	Pos       Pos
-	Content   string
-	TrimLeft  bool
-	TrimRight bool
+	Pos     Pos
+	Content string
 }
 
 // PrintBlock represents a block that will HTML escape the contents before outputting
 type PrintBlock struct {
-	Pos       Pos
-	Content   string
-	TrimLeft  bool
-	TrimRight bool
+	Pos     Pos
+	Content string
 }
 
 // RawPrintBlock represents a block of the template that is printed out to the writer.
 type RawPrintBlock struct {
-	Pos       Pos
-	Content   string
-	TrimLeft  bool
-	TrimRight bool
+	Pos     Pos
+	Content string
 }
 
 // ComponentStartBlock represents the opening block of an ego component.
@@ -438,6 +405,11 @@ func stringSliceContains(a []string, v string) bool {
 	return false
 }
 
+type stackElem struct {
+	block Block
+	yield []Block
+}
+
 // AttrNames returns a sorted list of names for an attribute set.
 func AttrNames(attrs map[string]interface{}) []string {
 	a := make([]string, 0, len(attrs))

scanner.go

@@ -53,11 +53,11 @@ func (s *Scanner) Scan() (Block, error) {
 		}
 
 		// Special handling for ego blocks.
-		if s.peekN(4) == "<%==" || s.peekN(5) == "<%-==" {
+		if s.peekN(4) == "<%==" {
 			return s.scanRawPrintBlock()
-		} else if s.peekN(3) == "<%=" || s.peekN(4) == "<%-=" {
+		} else if s.peekN(3) == "<%=" {
 			return s.scanPrintBlock()
-		} else if s.peekN(2) == "<%" || s.peekN(3) == "<%-" {
+		} else if s.peekN(2) == "<%" {
 			return s.scanCodeBlock()
 		}
 
@@ -78,66 +78,45 @@ func (s *Scanner) scanTextBlock() (*TextBlock, error) {
 		buf.WriteRune(s.read())
 	}
 
-	b.Content = buf.String()
+	b.Content = string(buf.Bytes())
 
 	return b, nil
 }
 
 func (s *Scanner) scanCodeBlock() (*CodeBlock, error) {
 	b := &CodeBlock{Pos: s.pos}
+	assert(s.readN(2) == "<%")
 
-	if s.peekN(3) == "<%-" {
-		assert(s.readN(3) == "<%-")
-		b.TrimLeft = true
-	} else {
-		assert(s.readN(2) == "<%")
-	}
-
-	content, trimRight, err := s.scanContent()
+	content, err := s.scanContent()
 	if err != nil {
 		return nil, err
 	}
 	b.Content = content
-	b.TrimRight = trimRight
 
 	return b, nil
 }
 
 func (s *Scanner) scanPrintBlock() (*PrintBlock, error) {
 	b := &PrintBlock{Pos: s.pos}
+	assert(s.readN(3) == "<%=")
 
-	if s.peekN(3) == "<%-" {
-		assert(s.readN(4) == "<%-=")
-		b.TrimLeft = true
-	} else {
-		assert(s.readN(3) == "<%=")
-	}
-
-	content, trimRight, err := s.scanContent()
+	content, err := s.scanContent()
 	if err != nil {
 		return nil, err
 	}
 	b.Content = content
-	b.TrimRight = trimRight
 	return b, nil
 }
 
 func (s *Scanner) scanRawPrintBlock() (*RawPrintBlock, error) {
 	b := &RawPrintBlock{Pos: s.pos}
+	assert(s.readN(4) == "<%==")
 
-	if s.peekN(3) == "<%-" {
-		assert(s.readN(5) == "<%-==")
-		b.TrimLeft = true
-	} else {
-		assert(s.readN(4) == "<%==")
-	}
-
-	content, trimRight, err := s.scanContent()
+	content, err := s.scanContent()
 	if err != nil {
 		return nil, err
 	}
 	b.Content = content
-	b.TrimRight = trimRight
 	return b, nil
 }
 
@@ -345,26 +324,28 @@ func (s *Scanner) scanAttrEndBlock() (_ *AttrEndBlock, err error) {
 	return b, nil
 }
 
-// scans the reader until %> or -%> is reached.
-func (s *Scanner) scanContent() (string, bool, error) {
+// scans the reader until %> is reached.
+func (s *Scanner) scanContent() (string, error) {
 	var buf bytes.Buffer
-	var trimRight bool
 	for {
 		ch := s.read()
 		if ch == eof {
-			return "", false, &SyntaxError{Message: "Expected close tag, found EOF", Pos: s.pos}
-		} else if ch == '-' && s.peekN(2) == "%>" {
-			s.readN(2)
-			trimRight = true
-			break
-		} else if ch == '%' && s.peek() == '>' {
-			s.read()
-			break
+			return "", &SyntaxError{Message: "Expected close tag, found EOF", Pos: s.pos}
+		} else if ch == '%' {
+			ch := s.read()
+			if ch == eof {
+				return "", &SyntaxError{Message: "Expected close tag, found EOF", Pos: s.pos}
+			} else if ch == '>' {
+				break
+			} else {
+				buf.WriteRune('%')
+				buf.WriteRune(ch)
+			}
 		} else {
 			buf.WriteRune(ch)
 		}
 	}
-	return buf.String(), trimRight, nil
+	return string(buf.Bytes()), nil
 }
 
 func (s *Scanner) scanField() (*Field, error) {
@@ -615,6 +596,7 @@ func (s *Scanner) skipWhitespace() {
 	for ch := s.peek(); isWhitespace(ch); ch = s.peek() {
 		s.read()
 	}
+	return
 }
 
 const eof = rune(0)

scanner_test.go

@@ -62,45 +62,6 @@ func TestScanner(t *testing.T) {
 			}
 		})
 
-		t.Run("TrimLeft", func(t *testing.T) {
-			s := ego.NewScanner(bytes.NewBufferString(`<%- x := 1 %>`), "tmpl.ego")
-			if blk, err := s.Scan(); err != nil {
-				t.Fatal(err)
-			} else if blk, ok := blk.(*ego.CodeBlock); !ok {
-				t.Fatalf("unexpected block type: %T", blk)
-			} else if blk.Content != " x := 1 " {
-				t.Fatalf("unexpected content: %s", blk.Content)
-			} else if !blk.TrimLeft || blk.TrimRight {
-				t.Fatal("expected TrimLeft only")
-			}
-		})
-
-		t.Run("TrimRight", func(t *testing.T) {
-			s := ego.NewScanner(bytes.NewBufferString(`<% x := 1 -%>`), "tmpl.ego")
-			if blk, err := s.Scan(); err != nil {
-				t.Fatal(err)
-			} else if blk, ok := blk.(*ego.CodeBlock); !ok {
-				t.Fatalf("unexpected block type: %T", blk)
-			} else if blk.Content != " x := 1 " {
-				t.Fatalf("unexpected content: %s", blk.Content)
-			} else if blk.TrimLeft || !blk.TrimRight {
-				t.Fatal("expected TrimRight only")
-			}
-		})
-
-		t.Run("Trim", func(t *testing.T) {
-			s := ego.NewScanner(bytes.NewBufferString(`<%- x := 1 -%>`), "tmpl.ego")
-			if blk, err := s.Scan(); err != nil {
-				t.Fatal(err)
-			} else if blk, ok := blk.(*ego.CodeBlock); !ok {
-				t.Fatalf("unexpected block type: %T", blk)
-			} else if blk.Content != " x := 1 " {
-				t.Fatalf("unexpected content: %s", blk.Content)
-			} else if !blk.TrimLeft || !blk.TrimRight {
-				t.Fatal("expected TrimLeft and TrimRight")
-			}
-		})
-
 		t.Run("UnexpectedEOF/1", func(t *testing.T) {
 			s := ego.NewScanner(bytes.NewBufferString(`<%`), "tmpl.ego")
 			if _, err := s.Scan(); err == nil || err.Error() != `Expected close tag, found EOF at tmpl.ego:1` {