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Diffstat (limited to 'vendor/github.com/alecthomas/template/parse/node.go')
| -rw-r--r-- | vendor/github.com/alecthomas/template/parse/node.go | 834 |
1 files changed, 834 insertions, 0 deletions
diff --git a/vendor/github.com/alecthomas/template/parse/node.go b/vendor/github.com/alecthomas/template/parse/node.go new file mode 100644 index 000000000..55c37f6db --- /dev/null +++ b/vendor/github.com/alecthomas/template/parse/node.go @@ -0,0 +1,834 @@ +// 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) + Decl []*VariableNode // Variable declarations in lexical order. + Cmds []*CommandNode // The commands in lexical order. +} + +func (t *Tree) newPipeline(pos Pos, line int, decl []*VariableNode) *PipeNode { + return &PipeNode{tr: t, NodeType: NodePipe, Pos: pos, Line: line, Decl: decl} +} + +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 decl []*VariableNode + for _, d := range p.Decl { + decl = append(decl, d.Copy().(*VariableNode)) + } + n := p.tr.newPipeline(p.Pos, p.Line, decl) + 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) +} + +// 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 { + 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 { + 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()) +} |