text/template/parse: undo breaking API changes

golang.org/cl/84480 altered the API for the parse package for
clarity and consistency. However, the changes also broke the
API for consumers of the package. This CL reverts the API
to the previous spelling, adding only a single new exported
symbol.

Fixes #25968

Change-Id: Ieb81054b61eeac7df3bc3864ef446df43c26b80f
Reviewed-on: https://go-review.googlesource.com/120355
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>

2 files changed, 22 insertions, 22 deletions

diff --git a/src/text/template/parse/node.go b/src/text/template/parse/node.go
index 0bb96fc2e9..dca83dacce 100644
--- a/src/text/template/parse/node.go
+++ b/src/text/template/parse/node.go
@@ -144,15 +144,15 @@ func (t *TextNode) Copy() Node {
 type PipeNode struct {
 	NodeType
 	Pos
-	tr   *Tree
-	Line int            // The line number in the input. Deprecated: Kept for compatibility.
-	Decl bool           // The variables are being declared, not assigned
-	Vars []*AssignNode  // Variables in lexical order.
-	Cmds []*CommandNode // The commands in lexical order.
+	tr       *Tree
+	Line     int             // The line number in the input. Deprecated: Kept for compatibility.
+	IsAssign bool            // The variables are being assigned, not declared.
+	Decl     []*VariableNode // Variables in lexical order.
+	Cmds     []*CommandNode  // The commands in lexical order.
 }
 
-func (t *Tree) newPipeline(pos Pos, line int, vars []*AssignNode) *PipeNode {
-	return &PipeNode{tr: t, NodeType: NodePipe, Pos: pos, Line: line, Vars: vars}
+func (t *Tree) newPipeline(pos Pos, line int, vars []*VariableNode) *PipeNode {
+	return &PipeNode{tr: t, NodeType: NodePipe, Pos: pos, Line: line, Decl: vars}
 }
 
 func (p *PipeNode) append(command *CommandNode) {
@@ -161,8 +161,8 @@ func (p *PipeNode) append(command *CommandNode) {
 
 func (p *PipeNode) String() string {
 	s := ""
-	if len(p.Vars) > 0 {
-		for i, v := range p.Vars {
+	if len(p.Decl) > 0 {
+		for i, v := range p.Decl {
 			if i > 0 {
 				s += ", "
 			}
@@ -187,12 +187,12 @@ func (p *PipeNode) CopyPipe() *PipeNode {
 	if p == nil {
 		return p
 	}
-	var vars []*AssignNode
-	for _, d := range p.Vars {
-		vars = append(vars, d.Copy().(*AssignNode))
+	var vars []*VariableNode
+	for _, d := range p.Decl {
+		vars = append(vars, d.Copy().(*VariableNode))
 	}
 	n := p.tr.newPipeline(p.Pos, p.Line, vars)
-	n.Decl = p.Decl
+	n.IsAssign = p.IsAssign
 	for _, c := range p.Cmds {
 		n.append(c.Copy().(*CommandNode))
 	}
@@ -321,18 +321,18 @@ func (i *IdentifierNode) Copy() Node {
 
 // AssignNode holds a list of variable names, possibly with chained field
 // accesses. The dollar sign is part of the (first) name.
-type AssignNode struct {
+type VariableNode struct {
 	NodeType
 	Pos
 	tr    *Tree
 	Ident []string // Variable name and fields in lexical order.
 }
 
-func (t *Tree) newVariable(pos Pos, ident string) *AssignNode {
-	return &AssignNode{tr: t, NodeType: NodeVariable, Pos: pos, Ident: strings.Split(ident, ".")}
+func (t *Tree) newVariable(pos Pos, ident string) *VariableNode {
+	return &VariableNode{tr: t, NodeType: NodeVariable, Pos: pos, Ident: strings.Split(ident, ".")}
 }
 
-func (v *AssignNode) String() string {
+func (v *VariableNode) String() string {
 	s := ""
 	for i, id := range v.Ident {
 		if i > 0 {
@@ -343,12 +343,12 @@ func (v *AssignNode) String() string {
 	return s
 }
 
-func (v *AssignNode) tree() *Tree {
+func (v *VariableNode) tree() *Tree {
 	return v.tr
 }
 
-func (v *AssignNode) Copy() Node {
-	return &AssignNode{tr: v.tr, NodeType: NodeVariable, Pos: v.Pos, Ident: append([]string{}, v.Ident...)}
+func (v *VariableNode) Copy() Node {
+	return &VariableNode{tr: v.tr, NodeType: NodeVariable, Pos: v.Pos, Ident: append([]string{}, v.Ident...)}
 }
 
 // DotNode holds the special identifier '.'.
diff --git a/src/text/template/parse/parse.go b/src/text/template/parse/parse.go
index 34dc41c620..cb9b44e9da 100644
--- a/src/text/template/parse/parse.go
+++ b/src/text/template/parse/parse.go
@@ -384,7 +384,7 @@ func (t *Tree) action() (n Node) {
 //	declarations? command ('|' command)*
 func (t *Tree) pipeline(context string) (pipe *PipeNode) {
 	decl := false
-	var vars []*AssignNode
+	var vars []*VariableNode
 	token := t.peekNonSpace()
 	pos := token.pos
 	// Are there declarations or assignments?
@@ -422,7 +422,7 @@ func (t *Tree) pipeline(context string) (pipe *PipeNode) {
 		break
 	}
 	pipe = t.newPipeline(pos, token.line, vars)
-	pipe.Decl = decl
+	pipe.IsAssign = !decl
 	for {
 		switch token := t.nextNonSpace(); token.typ {
 		case itemRightDelim, itemRightParen: