template/parse: give if, range, and with a common representation.

No external changes.

R=nigeltao
CC=golang-dev
https://golang.org/cl/4940042

diff --git a/src/pkg/template/parse/node.go b/src/pkg/template/parse/node.go
index 6f0b429b958d30abf14e1ee4d51cbd84360f545f..7411327a6512724bc8f6b4f210ab5b86fe83d513 100644 (file)
--- a/src/pkg/template/parse/node.go
+++ b/src/pkg/template/parse/node.go
@@ -390,8 +390,8 @@ func (e *elseNode) String() string {
        return "{{else}}"
 }
 
-// IfNode represents an {{if}} action and its commands.
-type IfNode struct {
+// BranchNode is the common representation of if, range, and with.
+type BranchNode struct {
        NodeType
        Line     int       // The line number in the input.
        Pipe     *PipeNode // The pipeline to be evaluated.
@@ -399,35 +399,49 @@ type IfNode struct {
        ElseList *ListNode // What to execute if the value is empty (nil if absent).
 }
 
-func newIf(line int, pipe *PipeNode, list, elseList *ListNode) *IfNode {
-       return &IfNode{NodeType: NodeIf, Line: line, Pipe: pipe, List: list, ElseList: elseList}
+func (b *BranchNode) String() string {
+       name := ""
+       switch b.NodeType {
+       case NodeIf:
+               name = "if"
+       case NodeRange:
+               name = "range"
+       case NodeWith:
+               name = "with"
+       default:
+               panic("unknown branch type")
+       }
+       if b.ElseList != nil {
+               return fmt.Sprintf("({{%s %s}} %s {{else}} %s)", name, b.Pipe, b.List, b.ElseList)
+       }
+       return fmt.Sprintf("({{%s %s}} %s)", name, b.Pipe, b.List)
 }
 
-func (i *IfNode) String() string {
-       if i.ElseList != nil {
-               return fmt.Sprintf("({{if %s}} %s {{else}} %s)", i.Pipe, i.List, i.ElseList)
-       }
-       return fmt.Sprintf("({{if %s}} %s)", i.Pipe, i.List)
+// IfNode represents an {{if}} action and its commands.
+type IfNode struct {
+       BranchNode
+}
+
+func newIf(line int, pipe *PipeNode, list, elseList *ListNode) *IfNode {
+       return &IfNode{BranchNode{NodeType: NodeIf, Line: line, Pipe: pipe, List: list, ElseList: elseList}}
 }
 
 // RangeNode represents a {{range}} action and its commands.
 type RangeNode struct {
-       NodeType
-       Line     int       // The line number in the input.
-       Pipe     *PipeNode // The pipeline to be evaluated.
-       List     *ListNode // What to execute if the value is non-empty.
-       ElseList *ListNode // What to execute if the value is empty (nil if absent).
+       BranchNode
 }
 
 func newRange(line int, pipe *PipeNode, list, elseList *ListNode) *RangeNode {
-       return &RangeNode{NodeType: NodeRange, Line: line, Pipe: pipe, List: list, ElseList: elseList}
+       return &RangeNode{BranchNode{NodeType: NodeRange, Line: line, Pipe: pipe, List: list, ElseList: elseList}}
 }
 
-func (r *RangeNode) String() string {
-       if r.ElseList != nil {
-               return fmt.Sprintf("({{range %s}} %s {{else}} %s)", r.Pipe, r.List, r.ElseList)
-       }
-       return fmt.Sprintf("({{range %s}} %s)", r.Pipe, r.List)
+// WithNode represents a {{with}} action and its commands.
+type WithNode struct {
+       BranchNode
+}
+
+func newWith(line int, pipe *PipeNode, list, elseList *ListNode) *WithNode {
+       return &WithNode{BranchNode{NodeType: NodeWith, Line: line, Pipe: pipe, List: list, ElseList: elseList}}
 }
 
 // TemplateNode represents a {{template}} action.
@@ -448,23 +462,3 @@ func (t *TemplateNode) String() string {
        }
        return fmt.Sprintf("{{template %q %s}}", t.Name, t.Pipe)
 }
-
-// WithNode represents a {{with}} action and its commands.
-type WithNode struct {
-       NodeType
-       Line     int       // The line number in the input.
-       Pipe     *PipeNode // The pipeline to be evaluated.
-       List     *ListNode // What to execute if the value is non-empty.
-       ElseList *ListNode // What to execute if the value is empty (nil if absent).
-}
-
-func newWith(line int, pipe *PipeNode, list, elseList *ListNode) *WithNode {
-       return &WithNode{NodeType: NodeWith, Line: line, Pipe: pipe, List: list, ElseList: elseList}
-}
-
-func (w *WithNode) String() string {
-       if w.ElseList != nil {
-               return fmt.Sprintf("({{with %s}} %s {{else}} %s)", w.Pipe, w.List, w.ElseList)
-       }
-       return fmt.Sprintf("({{with %s}} %s)", w.Pipe, w.List)
-}