ref: 746ba803afee8f0f56ee0655cc55087f1822d39c
dir: /tpl/internal/go_templates/texttemplate/parse/node.go/
// 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. ) // 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...)} } // 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) } // 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 { 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()) }