// 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 (
"bytes"
"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
}
// 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.
)
// 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 {
b := new(bytes.Buffer)
for _, n := range l.Nodes {
fmt.Fprint(b, n)
}
return b.String()
}
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) 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...)}
}
// 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 {
s := ""
if len(p.Decl) > 0 {
for i, v := range p.Decl {
if i > 0 {
s += ", "
}
s += v.String()
}
s += " := "
}
for i, c := range p.Cmds {
if i > 0 {
s += " | "
}
s += c.String()
}
return s
}
func (p *PipeNode) tree() *Tree {
return p.tr
}
func (p *PipeNode) CopyPipe() *PipeNode {
if p == nil {
return p
}
var vars []*VariableNode
for _, d := range p.Decl {
vars = append(vars, 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 {
return fmt.Sprintf("{{%s}}", a.Pipe)
}
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 {
s := ""
for i, arg := range c.Args {
if i > 0 {
s += " "
}
if arg, ok := arg.(*PipeNode); ok {
s += "(" + arg.String() + ")"
continue
}
s += arg.String()
}
return s
}
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) tree() *Tree {
return i.tr
}
func (i *IdentifierNode) Copy() Node {
return NewIdentifier(i.Ident).SetTree(i.tr).SetPos(i.Pos)
}
// AssignNode 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 {
s := ""
for i, id := range v.Ident {
if i > 0 {
s += "."
}
s += id
}
return s
}
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) 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) 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 {
s := ""
for _, id := range f.Ident {
s += "." + id
}
return s
}
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 {
s := c.Node.String()
if _, ok := c.Node.(*PipeNode); ok {
s = "(" + s + ")"
}
for _, field := range c.Field {
s += "." + field
}
return s
}
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) 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) 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) 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) 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) 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 {
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{{end}}", name, b.Pipe, b.List, b.ElseList)
}
return fmt.Sprintf("{{%s %s}}%s{{end}}", name, b.Pipe, b.List)
}
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 {
if t.Pipe == nil {
return fmt.Sprintf("{{template %q}}", t.Name)
}
return fmt.Sprintf("{{template %q %s}}", t.Name, t.Pipe)
}
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())
}
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