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-rw-r--r--src/text/template/parse/node.go972
1 files changed, 972 insertions, 0 deletions
diff --git a/src/text/template/parse/node.go b/src/text/template/parse/node.go
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+++ b/src/text/template/parse/node.go
@@ -0,0 +1,972 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Parse nodes.
+
+package parse
+
+import (
+ "fmt"
+ "strconv"
+ "strings"
+)
+
+var textFormat = "%s" // Changed to "%q" in tests for better error messages.
+
+// A Node is an element in the parse tree. The interface is trivial.
+// The interface contains an unexported method so that only
+// types local to this package can satisfy it.
+type Node interface {
+ Type() NodeType
+ String() string
+ // Copy does a deep copy of the Node and all its components.
+ // To avoid type assertions, some XxxNodes also have specialized
+ // CopyXxx methods that return *XxxNode.
+ Copy() Node
+ Position() Pos // byte position of start of node in full original input string
+ // tree returns the containing *Tree.
+ // It is unexported so all implementations of Node are in this package.
+ tree() *Tree
+ // writeTo writes the String output to the builder.
+ writeTo(*strings.Builder)
+}
+
+// NodeType identifies the type of a parse tree node.
+type NodeType int
+
+// Pos represents a byte position in the original input text from which
+// this template was parsed.
+type Pos int
+
+func (p Pos) Position() Pos {
+ return p
+}
+
+// Type returns itself and provides an easy default implementation
+// for embedding in a Node. Embedded in all non-trivial Nodes.
+func (t NodeType) Type() NodeType {
+ return t
+}
+
+const (
+ NodeText NodeType = iota // Plain text.
+ NodeAction // A non-control action such as a field evaluation.
+ NodeBool // A boolean constant.
+ NodeChain // A sequence of field accesses.
+ NodeCommand // An element of a pipeline.
+ NodeDot // The cursor, dot.
+ nodeElse // An else action. Not added to tree.
+ nodeEnd // An end action. Not added to tree.
+ NodeField // A field or method name.
+ NodeIdentifier // An identifier; always a function name.
+ NodeIf // An if action.
+ NodeList // A list of Nodes.
+ NodeNil // An untyped nil constant.
+ NodeNumber // A numerical constant.
+ NodePipe // A pipeline of commands.
+ NodeRange // A range action.
+ NodeString // A string constant.
+ NodeTemplate // A template invocation action.
+ NodeVariable // A $ variable.
+ NodeWith // A with action.
+ NodeComment // A comment.
+)
+
+// Nodes.
+
+// ListNode holds a sequence of nodes.
+type ListNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Nodes []Node // The element nodes in lexical order.
+}
+
+func (t *Tree) newList(pos Pos) *ListNode {
+ return &ListNode{tr: t, NodeType: NodeList, Pos: pos}
+}
+
+func (l *ListNode) append(n Node) {
+ l.Nodes = append(l.Nodes, n)
+}
+
+func (l *ListNode) tree() *Tree {
+ return l.tr
+}
+
+func (l *ListNode) String() string {
+ var sb strings.Builder
+ l.writeTo(&sb)
+ return sb.String()
+}
+
+func (l *ListNode) writeTo(sb *strings.Builder) {
+ for _, n := range l.Nodes {
+ n.writeTo(sb)
+ }
+}
+
+func (l *ListNode) CopyList() *ListNode {
+ if l == nil {
+ return l
+ }
+ n := l.tr.newList(l.Pos)
+ for _, elem := range l.Nodes {
+ n.append(elem.Copy())
+ }
+ return n
+}
+
+func (l *ListNode) Copy() Node {
+ return l.CopyList()
+}
+
+// TextNode holds plain text.
+type TextNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Text []byte // The text; may span newlines.
+}
+
+func (t *Tree) newText(pos Pos, text string) *TextNode {
+ return &TextNode{tr: t, NodeType: NodeText, Pos: pos, Text: []byte(text)}
+}
+
+func (t *TextNode) String() string {
+ return fmt.Sprintf(textFormat, t.Text)
+}
+
+func (t *TextNode) writeTo(sb *strings.Builder) {
+ sb.WriteString(t.String())
+}
+
+func (t *TextNode) tree() *Tree {
+ return t.tr
+}
+
+func (t *TextNode) Copy() Node {
+ return &TextNode{tr: t.tr, NodeType: NodeText, Pos: t.Pos, Text: append([]byte{}, t.Text...)}
+}
+
+// CommentNode holds a comment.
+type CommentNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Text string // Comment text.
+}
+
+func (t *Tree) newComment(pos Pos, text string) *CommentNode {
+ return &CommentNode{tr: t, NodeType: NodeComment, Pos: pos, Text: text}
+}
+
+func (c *CommentNode) String() string {
+ var sb strings.Builder
+ c.writeTo(&sb)
+ return sb.String()
+}
+
+func (c *CommentNode) writeTo(sb *strings.Builder) {
+ sb.WriteString("{{")
+ sb.WriteString(c.Text)
+ sb.WriteString("}}")
+}
+
+func (c *CommentNode) tree() *Tree {
+ return c.tr
+}
+
+func (c *CommentNode) Copy() Node {
+ return &CommentNode{tr: c.tr, NodeType: NodeComment, Pos: c.Pos, Text: c.Text}
+}
+
+// PipeNode holds a pipeline with optional declaration
+type PipeNode struct {
+ NodeType
+ Pos
+ 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 []*VariableNode) *PipeNode {
+ return &PipeNode{tr: t, NodeType: NodePipe, Pos: pos, Line: line, Decl: vars}
+}
+
+func (p *PipeNode) append(command *CommandNode) {
+ p.Cmds = append(p.Cmds, command)
+}
+
+func (p *PipeNode) String() string {
+ var sb strings.Builder
+ p.writeTo(&sb)
+ return sb.String()
+}
+
+func (p *PipeNode) writeTo(sb *strings.Builder) {
+ if len(p.Decl) > 0 {
+ for i, v := range p.Decl {
+ if i > 0 {
+ sb.WriteString(", ")
+ }
+ v.writeTo(sb)
+ }
+ sb.WriteString(" := ")
+ }
+ for i, c := range p.Cmds {
+ if i > 0 {
+ sb.WriteString(" | ")
+ }
+ c.writeTo(sb)
+ }
+}
+
+func (p *PipeNode) tree() *Tree {
+ return p.tr
+}
+
+func (p *PipeNode) CopyPipe() *PipeNode {
+ if p == nil {
+ return p
+ }
+ vars := make([]*VariableNode, len(p.Decl))
+ for i, d := range p.Decl {
+ vars[i] = d.Copy().(*VariableNode)
+ }
+ n := p.tr.newPipeline(p.Pos, p.Line, vars)
+ n.IsAssign = p.IsAssign
+ for _, c := range p.Cmds {
+ n.append(c.Copy().(*CommandNode))
+ }
+ return n
+}
+
+func (p *PipeNode) Copy() Node {
+ return p.CopyPipe()
+}
+
+// ActionNode holds an action (something bounded by delimiters).
+// Control actions have their own nodes; ActionNode represents simple
+// ones such as field evaluations and parenthesized pipelines.
+type ActionNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Line int // The line number in the input. Deprecated: Kept for compatibility.
+ Pipe *PipeNode // The pipeline in the action.
+}
+
+func (t *Tree) newAction(pos Pos, line int, pipe *PipeNode) *ActionNode {
+ return &ActionNode{tr: t, NodeType: NodeAction, Pos: pos, Line: line, Pipe: pipe}
+}
+
+func (a *ActionNode) String() string {
+ var sb strings.Builder
+ a.writeTo(&sb)
+ return sb.String()
+}
+
+func (a *ActionNode) writeTo(sb *strings.Builder) {
+ sb.WriteString("{{")
+ a.Pipe.writeTo(sb)
+ sb.WriteString("}}")
+}
+
+func (a *ActionNode) tree() *Tree {
+ return a.tr
+}
+
+func (a *ActionNode) Copy() Node {
+ return a.tr.newAction(a.Pos, a.Line, a.Pipe.CopyPipe())
+
+}
+
+// CommandNode holds a command (a pipeline inside an evaluating action).
+type CommandNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Args []Node // Arguments in lexical order: Identifier, field, or constant.
+}
+
+func (t *Tree) newCommand(pos Pos) *CommandNode {
+ return &CommandNode{tr: t, NodeType: NodeCommand, Pos: pos}
+}
+
+func (c *CommandNode) append(arg Node) {
+ c.Args = append(c.Args, arg)
+}
+
+func (c *CommandNode) String() string {
+ var sb strings.Builder
+ c.writeTo(&sb)
+ return sb.String()
+}
+
+func (c *CommandNode) writeTo(sb *strings.Builder) {
+ for i, arg := range c.Args {
+ if i > 0 {
+ sb.WriteByte(' ')
+ }
+ if arg, ok := arg.(*PipeNode); ok {
+ sb.WriteByte('(')
+ arg.writeTo(sb)
+ sb.WriteByte(')')
+ continue
+ }
+ arg.writeTo(sb)
+ }
+}
+
+func (c *CommandNode) tree() *Tree {
+ return c.tr
+}
+
+func (c *CommandNode) Copy() Node {
+ if c == nil {
+ return c
+ }
+ n := c.tr.newCommand(c.Pos)
+ for _, c := range c.Args {
+ n.append(c.Copy())
+ }
+ return n
+}
+
+// IdentifierNode holds an identifier.
+type IdentifierNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Ident string // The identifier's name.
+}
+
+// NewIdentifier returns a new IdentifierNode with the given identifier name.
+func NewIdentifier(ident string) *IdentifierNode {
+ return &IdentifierNode{NodeType: NodeIdentifier, Ident: ident}
+}
+
+// SetPos sets the position. NewIdentifier is a public method so we can't modify its signature.
+// Chained for convenience.
+// TODO: fix one day?
+func (i *IdentifierNode) SetPos(pos Pos) *IdentifierNode {
+ i.Pos = pos
+ return i
+}
+
+// SetTree sets the parent tree for the node. NewIdentifier is a public method so we can't modify its signature.
+// Chained for convenience.
+// TODO: fix one day?
+func (i *IdentifierNode) SetTree(t *Tree) *IdentifierNode {
+ i.tr = t
+ return i
+}
+
+func (i *IdentifierNode) String() string {
+ return i.Ident
+}
+
+func (i *IdentifierNode) writeTo(sb *strings.Builder) {
+ sb.WriteString(i.String())
+}
+
+func (i *IdentifierNode) tree() *Tree {
+ return i.tr
+}
+
+func (i *IdentifierNode) Copy() Node {
+ return NewIdentifier(i.Ident).SetTree(i.tr).SetPos(i.Pos)
+}
+
+// VariableNode holds a list of variable names, possibly with chained field
+// accesses. The dollar sign is part of the (first) name.
+type VariableNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Ident []string // Variable name and fields in lexical order.
+}
+
+func (t *Tree) newVariable(pos Pos, ident string) *VariableNode {
+ return &VariableNode{tr: t, NodeType: NodeVariable, Pos: pos, Ident: strings.Split(ident, ".")}
+}
+
+func (v *VariableNode) String() string {
+ var sb strings.Builder
+ v.writeTo(&sb)
+ return sb.String()
+}
+
+func (v *VariableNode) writeTo(sb *strings.Builder) {
+ for i, id := range v.Ident {
+ if i > 0 {
+ sb.WriteByte('.')
+ }
+ sb.WriteString(id)
+ }
+}
+
+func (v *VariableNode) tree() *Tree {
+ return v.tr
+}
+
+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 '.'.
+type DotNode struct {
+ NodeType
+ Pos
+ tr *Tree
+}
+
+func (t *Tree) newDot(pos Pos) *DotNode {
+ return &DotNode{tr: t, NodeType: NodeDot, Pos: pos}
+}
+
+func (d *DotNode) Type() NodeType {
+ // Override method on embedded NodeType for API compatibility.
+ // TODO: Not really a problem; could change API without effect but
+ // api tool complains.
+ return NodeDot
+}
+
+func (d *DotNode) String() string {
+ return "."
+}
+
+func (d *DotNode) writeTo(sb *strings.Builder) {
+ sb.WriteString(d.String())
+}
+
+func (d *DotNode) tree() *Tree {
+ return d.tr
+}
+
+func (d *DotNode) Copy() Node {
+ return d.tr.newDot(d.Pos)
+}
+
+// NilNode holds the special identifier 'nil' representing an untyped nil constant.
+type NilNode struct {
+ NodeType
+ Pos
+ tr *Tree
+}
+
+func (t *Tree) newNil(pos Pos) *NilNode {
+ return &NilNode{tr: t, NodeType: NodeNil, Pos: pos}
+}
+
+func (n *NilNode) Type() NodeType {
+ // Override method on embedded NodeType for API compatibility.
+ // TODO: Not really a problem; could change API without effect but
+ // api tool complains.
+ return NodeNil
+}
+
+func (n *NilNode) String() string {
+ return "nil"
+}
+
+func (n *NilNode) writeTo(sb *strings.Builder) {
+ sb.WriteString(n.String())
+}
+
+func (n *NilNode) tree() *Tree {
+ return n.tr
+}
+
+func (n *NilNode) Copy() Node {
+ return n.tr.newNil(n.Pos)
+}
+
+// FieldNode holds a field (identifier starting with '.').
+// The names may be chained ('.x.y').
+// The period is dropped from each ident.
+type FieldNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Ident []string // The identifiers in lexical order.
+}
+
+func (t *Tree) newField(pos Pos, ident string) *FieldNode {
+ return &FieldNode{tr: t, NodeType: NodeField, Pos: pos, Ident: strings.Split(ident[1:], ".")} // [1:] to drop leading period
+}
+
+func (f *FieldNode) String() string {
+ var sb strings.Builder
+ f.writeTo(&sb)
+ return sb.String()
+}
+
+func (f *FieldNode) writeTo(sb *strings.Builder) {
+ for _, id := range f.Ident {
+ sb.WriteByte('.')
+ sb.WriteString(id)
+ }
+}
+
+func (f *FieldNode) tree() *Tree {
+ return f.tr
+}
+
+func (f *FieldNode) Copy() Node {
+ return &FieldNode{tr: f.tr, NodeType: NodeField, Pos: f.Pos, Ident: append([]string{}, f.Ident...)}
+}
+
+// ChainNode holds a term followed by a chain of field accesses (identifier starting with '.').
+// The names may be chained ('.x.y').
+// The periods are dropped from each ident.
+type ChainNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Node Node
+ Field []string // The identifiers in lexical order.
+}
+
+func (t *Tree) newChain(pos Pos, node Node) *ChainNode {
+ return &ChainNode{tr: t, NodeType: NodeChain, Pos: pos, Node: node}
+}
+
+// Add adds the named field (which should start with a period) to the end of the chain.
+func (c *ChainNode) Add(field string) {
+ if len(field) == 0 || field[0] != '.' {
+ panic("no dot in field")
+ }
+ field = field[1:] // Remove leading dot.
+ if field == "" {
+ panic("empty field")
+ }
+ c.Field = append(c.Field, field)
+}
+
+func (c *ChainNode) String() string {
+ var sb strings.Builder
+ c.writeTo(&sb)
+ return sb.String()
+}
+
+func (c *ChainNode) writeTo(sb *strings.Builder) {
+ if _, ok := c.Node.(*PipeNode); ok {
+ sb.WriteByte('(')
+ c.Node.writeTo(sb)
+ sb.WriteByte(')')
+ } else {
+ c.Node.writeTo(sb)
+ }
+ for _, field := range c.Field {
+ sb.WriteByte('.')
+ sb.WriteString(field)
+ }
+}
+
+func (c *ChainNode) tree() *Tree {
+ return c.tr
+}
+
+func (c *ChainNode) Copy() Node {
+ return &ChainNode{tr: c.tr, NodeType: NodeChain, Pos: c.Pos, Node: c.Node, Field: append([]string{}, c.Field...)}
+}
+
+// BoolNode holds a boolean constant.
+type BoolNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ True bool // The value of the boolean constant.
+}
+
+func (t *Tree) newBool(pos Pos, true bool) *BoolNode {
+ return &BoolNode{tr: t, NodeType: NodeBool, Pos: pos, True: true}
+}
+
+func (b *BoolNode) String() string {
+ if b.True {
+ return "true"
+ }
+ return "false"
+}
+
+func (b *BoolNode) writeTo(sb *strings.Builder) {
+ sb.WriteString(b.String())
+}
+
+func (b *BoolNode) tree() *Tree {
+ return b.tr
+}
+
+func (b *BoolNode) Copy() Node {
+ return b.tr.newBool(b.Pos, b.True)
+}
+
+// NumberNode holds a number: signed or unsigned integer, float, or complex.
+// The value is parsed and stored under all the types that can represent the value.
+// This simulates in a small amount of code the behavior of Go's ideal constants.
+type NumberNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ IsInt bool // Number has an integral value.
+ IsUint bool // Number has an unsigned integral value.
+ IsFloat bool // Number has a floating-point value.
+ IsComplex bool // Number is complex.
+ Int64 int64 // The signed integer value.
+ Uint64 uint64 // The unsigned integer value.
+ Float64 float64 // The floating-point value.
+ Complex128 complex128 // The complex value.
+ Text string // The original textual representation from the input.
+}
+
+func (t *Tree) newNumber(pos Pos, text string, typ itemType) (*NumberNode, error) {
+ n := &NumberNode{tr: t, NodeType: NodeNumber, Pos: pos, Text: text}
+ switch typ {
+ case itemCharConstant:
+ rune, _, tail, err := strconv.UnquoteChar(text[1:], text[0])
+ if err != nil {
+ return nil, err
+ }
+ if tail != "'" {
+ return nil, fmt.Errorf("malformed character constant: %s", text)
+ }
+ n.Int64 = int64(rune)
+ n.IsInt = true
+ n.Uint64 = uint64(rune)
+ n.IsUint = true
+ n.Float64 = float64(rune) // odd but those are the rules.
+ n.IsFloat = true
+ return n, nil
+ case itemComplex:
+ // fmt.Sscan can parse the pair, so let it do the work.
+ if _, err := fmt.Sscan(text, &n.Complex128); err != nil {
+ return nil, err
+ }
+ n.IsComplex = true
+ n.simplifyComplex()
+ return n, nil
+ }
+ // Imaginary constants can only be complex unless they are zero.
+ if len(text) > 0 && text[len(text)-1] == 'i' {
+ f, err := strconv.ParseFloat(text[:len(text)-1], 64)
+ if err == nil {
+ n.IsComplex = true
+ n.Complex128 = complex(0, f)
+ n.simplifyComplex()
+ return n, nil
+ }
+ }
+ // Do integer test first so we get 0x123 etc.
+ u, err := strconv.ParseUint(text, 0, 64) // will fail for -0; fixed below.
+ if err == nil {
+ n.IsUint = true
+ n.Uint64 = u
+ }
+ i, err := strconv.ParseInt(text, 0, 64)
+ if err == nil {
+ n.IsInt = true
+ n.Int64 = i
+ if i == 0 {
+ n.IsUint = true // in case of -0.
+ n.Uint64 = u
+ }
+ }
+ // If an integer extraction succeeded, promote the float.
+ if n.IsInt {
+ n.IsFloat = true
+ n.Float64 = float64(n.Int64)
+ } else if n.IsUint {
+ n.IsFloat = true
+ n.Float64 = float64(n.Uint64)
+ } else {
+ f, err := strconv.ParseFloat(text, 64)
+ if err == nil {
+ // If we parsed it as a float but it looks like an integer,
+ // it's a huge number too large to fit in an int. Reject it.
+ if !strings.ContainsAny(text, ".eEpP") {
+ return nil, fmt.Errorf("integer overflow: %q", text)
+ }
+ n.IsFloat = true
+ n.Float64 = f
+ // If a floating-point extraction succeeded, extract the int if needed.
+ if !n.IsInt && float64(int64(f)) == f {
+ n.IsInt = true
+ n.Int64 = int64(f)
+ }
+ if !n.IsUint && float64(uint64(f)) == f {
+ n.IsUint = true
+ n.Uint64 = uint64(f)
+ }
+ }
+ }
+ if !n.IsInt && !n.IsUint && !n.IsFloat {
+ return nil, fmt.Errorf("illegal number syntax: %q", text)
+ }
+ return n, nil
+}
+
+// simplifyComplex pulls out any other types that are represented by the complex number.
+// These all require that the imaginary part be zero.
+func (n *NumberNode) simplifyComplex() {
+ n.IsFloat = imag(n.Complex128) == 0
+ if n.IsFloat {
+ n.Float64 = real(n.Complex128)
+ n.IsInt = float64(int64(n.Float64)) == n.Float64
+ if n.IsInt {
+ n.Int64 = int64(n.Float64)
+ }
+ n.IsUint = float64(uint64(n.Float64)) == n.Float64
+ if n.IsUint {
+ n.Uint64 = uint64(n.Float64)
+ }
+ }
+}
+
+func (n *NumberNode) String() string {
+ return n.Text
+}
+
+func (n *NumberNode) writeTo(sb *strings.Builder) {
+ sb.WriteString(n.String())
+}
+
+func (n *NumberNode) tree() *Tree {
+ return n.tr
+}
+
+func (n *NumberNode) Copy() Node {
+ nn := new(NumberNode)
+ *nn = *n // Easy, fast, correct.
+ return nn
+}
+
+// StringNode holds a string constant. The value has been "unquoted".
+type StringNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Quoted string // The original text of the string, with quotes.
+ Text string // The string, after quote processing.
+}
+
+func (t *Tree) newString(pos Pos, orig, text string) *StringNode {
+ return &StringNode{tr: t, NodeType: NodeString, Pos: pos, Quoted: orig, Text: text}
+}
+
+func (s *StringNode) String() string {
+ return s.Quoted
+}
+
+func (s *StringNode) writeTo(sb *strings.Builder) {
+ sb.WriteString(s.String())
+}
+
+func (s *StringNode) tree() *Tree {
+ return s.tr
+}
+
+func (s *StringNode) Copy() Node {
+ return s.tr.newString(s.Pos, s.Quoted, s.Text)
+}
+
+// endNode represents an {{end}} action.
+// It does not appear in the final parse tree.
+type endNode struct {
+ NodeType
+ Pos
+ tr *Tree
+}
+
+func (t *Tree) newEnd(pos Pos) *endNode {
+ return &endNode{tr: t, NodeType: nodeEnd, Pos: pos}
+}
+
+func (e *endNode) String() string {
+ return "{{end}}"
+}
+
+func (e *endNode) writeTo(sb *strings.Builder) {
+ sb.WriteString(e.String())
+}
+
+func (e *endNode) tree() *Tree {
+ return e.tr
+}
+
+func (e *endNode) Copy() Node {
+ return e.tr.newEnd(e.Pos)
+}
+
+// elseNode represents an {{else}} action. Does not appear in the final tree.
+type elseNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Line int // The line number in the input. Deprecated: Kept for compatibility.
+}
+
+func (t *Tree) newElse(pos Pos, line int) *elseNode {
+ return &elseNode{tr: t, NodeType: nodeElse, Pos: pos, Line: line}
+}
+
+func (e *elseNode) Type() NodeType {
+ return nodeElse
+}
+
+func (e *elseNode) String() string {
+ return "{{else}}"
+}
+
+func (e *elseNode) writeTo(sb *strings.Builder) {
+ sb.WriteString(e.String())
+}
+
+func (e *elseNode) tree() *Tree {
+ return e.tr
+}
+
+func (e *elseNode) Copy() Node {
+ return e.tr.newElse(e.Pos, e.Line)
+}
+
+// BranchNode is the common representation of if, range, and with.
+type BranchNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Line int // The line number in the input. Deprecated: Kept for compatibility.
+ 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 (b *BranchNode) String() string {
+ var sb strings.Builder
+ b.writeTo(&sb)
+ return sb.String()
+}
+
+func (b *BranchNode) writeTo(sb *strings.Builder) {
+ name := ""
+ switch b.NodeType {
+ case NodeIf:
+ name = "if"
+ case NodeRange:
+ name = "range"
+ case NodeWith:
+ name = "with"
+ default:
+ panic("unknown branch type")
+ }
+ sb.WriteString("{{")
+ sb.WriteString(name)
+ sb.WriteByte(' ')
+ b.Pipe.writeTo(sb)
+ sb.WriteString("}}")
+ b.List.writeTo(sb)
+ if b.ElseList != nil {
+ sb.WriteString("{{else}}")
+ b.ElseList.writeTo(sb)
+ }
+ sb.WriteString("{{end}}")
+}
+
+func (b *BranchNode) tree() *Tree {
+ return b.tr
+}
+
+func (b *BranchNode) Copy() Node {
+ switch b.NodeType {
+ case NodeIf:
+ return b.tr.newIf(b.Pos, b.Line, b.Pipe, b.List, b.ElseList)
+ case NodeRange:
+ return b.tr.newRange(b.Pos, b.Line, b.Pipe, b.List, b.ElseList)
+ case NodeWith:
+ return b.tr.newWith(b.Pos, b.Line, b.Pipe, b.List, b.ElseList)
+ default:
+ panic("unknown branch type")
+ }
+}
+
+// IfNode represents an {{if}} action and its commands.
+type IfNode struct {
+ BranchNode
+}
+
+func (t *Tree) newIf(pos Pos, line int, pipe *PipeNode, list, elseList *ListNode) *IfNode {
+ return &IfNode{BranchNode{tr: t, NodeType: NodeIf, Pos: pos, Line: line, Pipe: pipe, List: list, ElseList: elseList}}
+}
+
+func (i *IfNode) Copy() Node {
+ return i.tr.newIf(i.Pos, i.Line, i.Pipe.CopyPipe(), i.List.CopyList(), i.ElseList.CopyList())
+}
+
+// RangeNode represents a {{range}} action and its commands.
+type RangeNode struct {
+ BranchNode
+}
+
+func (t *Tree) newRange(pos Pos, line int, pipe *PipeNode, list, elseList *ListNode) *RangeNode {
+ return &RangeNode{BranchNode{tr: t, NodeType: NodeRange, Pos: pos, Line: line, Pipe: pipe, List: list, ElseList: elseList}}
+}
+
+func (r *RangeNode) Copy() Node {
+ return r.tr.newRange(r.Pos, r.Line, r.Pipe.CopyPipe(), r.List.CopyList(), r.ElseList.CopyList())
+}
+
+// WithNode represents a {{with}} action and its commands.
+type WithNode struct {
+ BranchNode
+}
+
+func (t *Tree) newWith(pos Pos, line int, pipe *PipeNode, list, elseList *ListNode) *WithNode {
+ return &WithNode{BranchNode{tr: t, NodeType: NodeWith, Pos: pos, Line: line, Pipe: pipe, List: list, ElseList: elseList}}
+}
+
+func (w *WithNode) Copy() Node {
+ return w.tr.newWith(w.Pos, w.Line, w.Pipe.CopyPipe(), w.List.CopyList(), w.ElseList.CopyList())
+}
+
+// TemplateNode represents a {{template}} action.
+type TemplateNode struct {
+ NodeType
+ Pos
+ tr *Tree
+ Line int // The line number in the input. Deprecated: Kept for compatibility.
+ Name string // The name of the template (unquoted).
+ Pipe *PipeNode // The command to evaluate as dot for the template.
+}
+
+func (t *Tree) newTemplate(pos Pos, line int, name string, pipe *PipeNode) *TemplateNode {
+ return &TemplateNode{tr: t, NodeType: NodeTemplate, Pos: pos, Line: line, Name: name, Pipe: pipe}
+}
+
+func (t *TemplateNode) String() string {
+ var sb strings.Builder
+ t.writeTo(&sb)
+ return sb.String()
+}
+
+func (t *TemplateNode) writeTo(sb *strings.Builder) {
+ sb.WriteString("{{template ")
+ sb.WriteString(strconv.Quote(t.Name))
+ if t.Pipe != nil {
+ sb.WriteByte(' ')
+ t.Pipe.writeTo(sb)
+ }
+ sb.WriteString("}}")
+}
+
+func (t *TemplateNode) tree() *Tree {
+ return t.tr
+}
+
+func (t *TemplateNode) Copy() Node {
+ return t.tr.newTemplate(t.Pos, t.Line, t.Name, t.Pipe.CopyPipe())
+}