Documentation
¶
Overview ¶
Package ast declares the types used to represent syntax trees for CUE packages.
Index ¶
- Variables
- func AddComment(n Node, cg *CommentGroup)
- func Embed(x Expr) *embedding
- func IsValidIdent(ident string) bool
- func LabelName(l Label) (name string, isIdent bool, err error)
- func Name(n Node) string
- func ParseIdent(n *Ident) (string, error)deprecated
- func QuoteIdent(ident string) (string, error)deprecated
- func SetComments(n Node, cgs []*CommentGroup)
- func SetPos(n Node, p token.Pos)
- func SetRelPos(n Node, p token.RelPos)
- func Walk(node Node, before func(Node) bool, after func(Node))
- type Alias
- type Attribute
- type BadDecl
- type BadExpr
- type BasicLit
- type BinaryExpr
- type BottomLit
- type CallExpr
- type Clause
- type Comment
- type CommentGroup
- type Comprehension
- type Decl
- type Ellipsis
- type EmbedDecl
- type Expr
- type Field
- type File
- func (c *File) AddComment(cg *CommentGroup)
- func (c *File) Comments() []*CommentGroup
- func (f *File) End() token.Pos
- func (f *File) PackageName() string
- func (f *File) Pos() token.Pos
- func (f *File) Preamble() []Decl
- func (c *File) SetComments(cgs []*CommentGroup)
- func (f *File) VisitImports(fn func(d *ImportDecl))
- type ForClause
- type Ident
- type IfClause
- type ImportDecl
- type ImportSpec
- type IndexExpr
- type Interpolation
- type Label
- type LetClause
- type ListComprehension
- type ListLit
- type Node
- type Package
- type ParenExpr
- type SelectorExpr
- type SliceExpr
- type Spec
- type StructLit
- type TemplateLabeldeprecated
- type UnaryExpr
Constants ¶
This section is empty.
Variables ¶
var ErrIsExpression = errors.New("not a concrete label")
ErrIsExpression reports whether a label is an expression. This error is never returned directly. Use errors.Is or xerrors.Is.
Functions ¶
func AddComment ¶ added in v0.0.10
func AddComment(n Node, cg *CommentGroup)
AddComment adds the given comment to the node if it supports it. If a node does not support comments, such as for CommentGroup or Comment, this call has no effect.
func Embed ¶ added in v0.2.2
func Embed(x Expr) *embedding
Embed can be used in conjunction with NewStruct to embed values.
func IsValidIdent ¶ added in v0.0.14
func IsValidIdent(ident string) bool
IsValidIdent reports whether str is a valid identifier.
func LabelName ¶
func LabelName(l Label) (name string, isIdent bool, err error)
LabelName reports the name of a label, whether it is an identifier (it binds a value to a scope), and whether it is valid. Keywords that are allowed in label positions are interpreted accordingly.
Examples:
Label Result
foo "foo" true nil
true "true" true nil
"foo" "foo" false nil
"x-y" "x-y" false nil
"foo "" false invalid string
"\(x)" "" false errors.Is(err, ErrIsExpression)
X=foo "foo" true nil
func ParseIdent
deprecated
added in
v0.0.10
func ParseIdent(n *Ident) (string, error)
ParseIdent unquotes a possibly quoted identifier and validates if the result is valid.
Deprecated: quoted identifiers are deprecated. Use aliases.
func QuoteIdent
deprecated
added in
v0.0.10
func QuoteIdent(ident string) (string, error)
QuoteIdent quotes an identifier, if needed, and reports an error if the identifier is invalid.
Deprecated: quoted identifiers are deprecated. Use aliases.
func SetComments ¶ added in v0.0.10
func SetComments(n Node, cgs []*CommentGroup)
SetComments replaces all comments of n with the given set of comments. If a node does not support comments, such as for CommentGroup or Comment, this call has no effect.
func SetPos ¶ added in v0.0.10
func SetPos(n Node, p token.Pos)
SetPos sets a node to the given position, if possible.
func SetRelPos ¶ added in v0.0.10
func SetRelPos(n Node, p token.RelPos)
SetRelPos sets the relative position of a node without modifying its file position. Setting it to token.NoRelPos allows a node to adopt default formatting.
func Walk ¶
func Walk(node Node, before func(Node) bool, after func(Node))
Walk traverses an AST in depth-first order: It starts by calling f(node); node must not be nil. If before returns true, Walk invokes f recursively for each of the non-nil children of node, followed by a call of after. Both functions may be nil. If before is nil, it is assumed to always return true.
Types ¶
type Alias ¶
type Alias struct {
Ident *Ident // field name, always an Ident
Equal token.Pos // position of "="
Expr Expr // An Ident or SelectorExpr
// contains filtered or unexported fields
}
An Alias binds another field to the alias name in the current struct.
func (*Alias) AddComment ¶
func (c *Alias) AddComment(cg *CommentGroup)
func (*Alias) SetComments ¶ added in v0.0.10
func (c *Alias) SetComments(cgs []*CommentGroup)
type Attribute ¶
type Attribute struct {
At token.Pos
Text string // must be a valid attribute format.
// contains filtered or unexported fields
}
An Attribute provides meta data about a field.
func (*Attribute) AddComment ¶
func (c *Attribute) AddComment(cg *CommentGroup)
func (*Attribute) SetComments ¶ added in v0.0.10
func (c *Attribute) SetComments(cgs []*CommentGroup)
type BadDecl ¶
type BadDecl struct {
From, To token.Pos // position range of bad declaration
// contains filtered or unexported fields
}
A BadDecl node is a placeholder for declarations containing syntax errors for which no correct declaration nodes can be created.
func (*BadDecl) AddComment ¶
func (c *BadDecl) AddComment(cg *CommentGroup)
func (*BadDecl) SetComments ¶ added in v0.0.10
func (c *BadDecl) SetComments(cgs []*CommentGroup)
type BadExpr ¶
type BadExpr struct {
From, To token.Pos // position range of bad expression
// contains filtered or unexported fields
}
A BadExpr node is a placeholder for expressions containing syntax errors for which no correct expression nodes can be created. This is different from an ErrorExpr which represents an explicitly marked error in the source.
func (*BadExpr) AddComment ¶
func (c *BadExpr) AddComment(cg *CommentGroup)
func (*BadExpr) SetComments ¶ added in v0.0.10
func (c *BadExpr) SetComments(cgs []*CommentGroup)
type BasicLit ¶
type BasicLit struct {
ValuePos token.Pos // literal position
Kind token.Token // INT, FLOAT, DURATION, or STRING
Value string // literal string; e.g. 42, 0x7f, 3.14, 1_234_567, 1e-9, 2.4i, 'a', '\x7f', "foo", or '\m\n\o'
// contains filtered or unexported fields
}
A BasicLit node represents a literal of basic type.
func NewBool ¶ added in v0.1.0
func NewBool(b bool) *BasicLit
NewBool creates a new BasicLit with a bool value without position. Useful for ASTs generated by code other than the CUE parser.
func NewLit ¶ added in v0.1.0
func NewLit(tok token.Token, s string) *BasicLit
NewLit creates a new BasicLit with from a token type and string without position. Useful for ASTs generated by code other than the CUE parser.
func NewNull ¶ added in v0.2.1
func NewNull() *BasicLit
NewNull creates a new BasicLit configured to be a null value. Useful for ASTs generated by code other than the CUE parser.
func NewString ¶ added in v0.0.10
func NewString(str string) *BasicLit
NewString creates a new BasicLit with a string value without position. It quotes the given string. Useful for ASTs generated by code other than the CUE parser.
func (*BasicLit) AddComment ¶
func (c *BasicLit) AddComment(cg *CommentGroup)
func (*BasicLit) SetComments ¶ added in v0.0.10
func (c *BasicLit) SetComments(cgs []*CommentGroup)
type BinaryExpr ¶
type BinaryExpr struct {
X Expr // left operand
OpPos token.Pos // position of Op
Op token.Token // operator
Y Expr // right operand
// contains filtered or unexported fields
}
A BinaryExpr node represents a binary expression.
func (*BinaryExpr) AddComment ¶
func (c *BinaryExpr) AddComment(cg *CommentGroup)
func (*BinaryExpr) SetComments ¶ added in v0.0.10
func (c *BinaryExpr) SetComments(cgs []*CommentGroup)
type BottomLit ¶
type BottomLit struct {
Bottom token.Pos
// contains filtered or unexported fields
}
A BottomLit indicates an error.
func (*BottomLit) AddComment ¶
func (c *BottomLit) AddComment(cg *CommentGroup)
func (*BottomLit) SetComments ¶ added in v0.0.10
func (c *BottomLit) SetComments(cgs []*CommentGroup)
type CallExpr ¶
type CallExpr struct {
Fun Expr // function expression
Lparen token.Pos // position of "("
Args []Expr // function arguments; or nil
Rparen token.Pos // position of ")"
// contains filtered or unexported fields
}
A CallExpr node represents an expression followed by an argument list.
func NewCall ¶ added in v0.0.10
func NewCall(fun Expr, args ...Expr) *CallExpr
NewCall creates a new CallExpr. Useful for ASTs generated by code other than the CUE parser.
func (*CallExpr) AddComment ¶
func (c *CallExpr) AddComment(cg *CommentGroup)
func (*CallExpr) SetComments ¶ added in v0.0.10
func (c *CallExpr) SetComments(cgs []*CommentGroup)
type Clause ¶
type Clause interface {
Node
// contains filtered or unexported methods
}
Clause nodes are part of comprehensions.
type Comment ¶
type Comment struct {
Slash token.Pos // position of "/" starting the comment
Text string // comment text (excluding '\n' for //-style comments)
}
A Comment node represents a single //-style or /*-style comment.
func (*Comment) AddComment ¶
func (c *Comment) AddComment(*CommentGroup)
type CommentGroup ¶
type CommentGroup struct {
// TODO: remove and use the token position of the first comment.
Doc bool
Line bool // true if it is on the same line as the node's end pos.
// Position indicates where a comment should be attached if a node has
// multiple tokens. 0 means before the first token, 1 means before the
// second, etc. For instance, for a field, the positions are:
// <0> Label <1> ":" <2> Expr <3> "," <4>
Position int8
List []*Comment // len(List) > 0
// contains filtered or unexported fields
}
A CommentGroup represents a sequence of comments with no other tokens and no empty lines between.
func Comments ¶ added in v0.0.10
func Comments(n Node) []*CommentGroup
Comments returns all comments associated with a given node.
func (*CommentGroup) AddComment ¶
func (g *CommentGroup) AddComment(*CommentGroup)
func (*CommentGroup) Text ¶
func (g *CommentGroup) Text() string
Text returns the text of the comment. Comment markers (//, /*, and */), the first space of a line comment, and leading and trailing empty lines are removed. Multiple empty lines are reduced to one, and trailing space on lines is trimmed. Unless the result is empty, it is newline-terminated.
type Comprehension ¶ added in v0.0.10
type Comprehension struct {
Clauses []Clause // There must be at least one clause.
Value Expr // Must be a struct TODO: change to Struct
// contains filtered or unexported fields
}
A Comprehension node represents a comprehension declaration.
func (*Comprehension) AddComment ¶ added in v0.0.10
func (c *Comprehension) AddComment(cg *CommentGroup)
func (*Comprehension) Comments ¶ added in v0.0.10
func (c *Comprehension) Comments() []*CommentGroup
func (*Comprehension) SetComments ¶ added in v0.0.10
func (c *Comprehension) SetComments(cgs []*CommentGroup)
type Decl ¶
type Decl interface {
Node
// contains filtered or unexported methods
}
A Decl node is implemented by all declarations.
type Ellipsis ¶ added in v0.0.6
type Ellipsis struct {
Ellipsis token.Pos // open list if set
Type Expr // type for the remaining elements
// contains filtered or unexported fields
}
func (*Ellipsis) AddComment ¶ added in v0.0.6
func (c *Ellipsis) AddComment(cg *CommentGroup)
func (*Ellipsis) SetComments ¶ added in v0.0.10
func (c *Ellipsis) SetComments(cgs []*CommentGroup)
type EmbedDecl ¶ added in v0.0.5
type EmbedDecl struct {
Expr Expr
// contains filtered or unexported fields
}
An EmbedDecl node represents a single expression used as a declaration. The expressions in this declaration is what will be emitted as configuration output.
An EmbedDecl may only appear at the top level.
func (*EmbedDecl) AddComment ¶ added in v0.0.5
func (c *EmbedDecl) AddComment(cg *CommentGroup)
func (*EmbedDecl) SetComments ¶ added in v0.0.10
func (c *EmbedDecl) SetComments(cgs []*CommentGroup)
type Expr ¶
type Expr interface {
Node
// contains filtered or unexported methods
}
An Expr is implemented by all expression nodes.
func NewBinExpr ¶ added in v0.1.0
func NewBinExpr(op token.Token, operands ...Expr) Expr
NewBinExpr creates for list of expressions of length 2 or greater a chained binary expression of the form (((x1 op x2) op x3) ...). For lists of length 1 it returns the expression itself. It panics for empty lists. Useful for ASTs generated by code other than the CUE parser.
type Field ¶
type Field struct {
Label Label // must have at least one element.
Optional token.Pos
// No TokenPos: Value must be an StructLit with one field.
TokenPos token.Pos
Token token.Token // ':' or '::', ILLEGAL implies ':'
Value Expr // the value associated with this field.
Attrs []*Attribute
// contains filtered or unexported fields
}
A Field represents a field declaration in a struct.
func (*Field) AddComment ¶
func (c *Field) AddComment(cg *CommentGroup)
func (*Field) SetComments ¶ added in v0.0.10
func (c *Field) SetComments(cgs []*CommentGroup)
type File ¶
type File struct {
Filename string
Decls []Decl // top-level declarations; or nil
Imports []*ImportSpec // imports in this file
Unresolved []*Ident // unresolved identifiers in this file
// contains filtered or unexported fields
}
A File node represents a Go source file.
The Comments list contains all comments in the source file in order of appearance, including the comments that are pointed to from other nodes via Doc and Comment fields.
func (*File) AddComment ¶
func (c *File) AddComment(cg *CommentGroup)
func (*File) PackageName ¶ added in v0.1.0
func (f *File) PackageName() string
PackageName returns the package name associated with this file or "" if no package is associated.
func (*File) Preamble ¶ added in v0.3.0
func (f *File) Preamble() []Decl
Preamble returns the declarations of the preamble.
func (*File) SetComments ¶ added in v0.0.10
func (c *File) SetComments(cgs []*CommentGroup)
func (*File) VisitImports ¶ added in v0.3.0
func (f *File) VisitImports(fn func(d *ImportDecl))
type ForClause ¶
type ForClause struct {
For token.Pos
Key *Ident // allow pattern matching?
// TODO: change to Comma
Colon token.Pos
Value *Ident // allow pattern matching?
In token.Pos
Source Expr
// contains filtered or unexported fields
}
A ForClause node represents a for clause in a comprehension.
func (*ForClause) AddComment ¶
func (c *ForClause) AddComment(cg *CommentGroup)
func (*ForClause) SetComments ¶ added in v0.0.10
func (c *ForClause) SetComments(cgs []*CommentGroup)
type Ident ¶
type Ident struct {
NamePos token.Pos // identifier position
// This LHS path element may be an identifier. Possible forms:
// foo: a normal identifier
// "foo": JSON compatible
// <foo>: a template shorthand
Name string
Scope Node // scope in which node was found or nil if referring directly
Node Node
// contains filtered or unexported fields
}
An Ident node represents an left-hand side identifier.
func NewIdent ¶
func NewIdent(name string) *Ident
NewIdent creates a new Ident without position. Useful for ASTs generated by code other than the CUE parser.
func (*Ident) AddComment ¶
func (c *Ident) AddComment(cg *CommentGroup)
func (*Ident) SetComments ¶ added in v0.0.10
func (c *Ident) SetComments(cgs []*CommentGroup)
type IfClause ¶
type IfClause struct {
If token.Pos
Condition Expr
// contains filtered or unexported fields
}
A IfClause node represents an if guard clause in a comprehension.
func (*IfClause) AddComment ¶
func (c *IfClause) AddComment(cg *CommentGroup)
func (*IfClause) SetComments ¶ added in v0.0.10
func (c *IfClause) SetComments(cgs []*CommentGroup)
type ImportDecl ¶
type ImportDecl struct {
Import token.Pos
Lparen token.Pos // position of '(', if any
Specs []*ImportSpec
Rparen token.Pos // position of ')', if any
// contains filtered or unexported fields
}
A ImportDecl node represents a series of import declarations. A valid Lparen position (Lparen.Line > 0) indicates a parenthesized declaration.
func (*ImportDecl) AddComment ¶
func (c *ImportDecl) AddComment(cg *CommentGroup)
func (*ImportDecl) SetComments ¶ added in v0.0.10
func (c *ImportDecl) SetComments(cgs []*CommentGroup)
type ImportSpec ¶
type ImportSpec struct {
Name *Ident // local package name (including "."); or nil
Path *BasicLit // import path
EndPos token.Pos // end of spec (overrides Path.Pos if nonzero)
// contains filtered or unexported fields
}
An ImportSpec node represents a single package import.
func (*ImportSpec) AddComment ¶
func (c *ImportSpec) AddComment(cg *CommentGroup)
func (*ImportSpec) SetComments ¶ added in v0.0.10
func (c *ImportSpec) SetComments(cgs []*CommentGroup)
type IndexExpr ¶
type IndexExpr struct {
X Expr // expression
Lbrack token.Pos // position of "["
Index Expr // index expression
Rbrack token.Pos // position of "]"
// contains filtered or unexported fields
}
An IndexExpr node represents an expression followed by an index.
func (*IndexExpr) AddComment ¶
func (c *IndexExpr) AddComment(cg *CommentGroup)
func (*IndexExpr) SetComments ¶ added in v0.0.10
func (c *IndexExpr) SetComments(cgs []*CommentGroup)
type Interpolation ¶
type Interpolation struct {
Elts []Expr // interleaving of strings and expressions.
// contains filtered or unexported fields
}
A Interpolation node represents a string or bytes interpolation.
func (*Interpolation) AddComment ¶
func (c *Interpolation) AddComment(cg *CommentGroup)
func (*Interpolation) SetComments ¶ added in v0.0.10
func (c *Interpolation) SetComments(cgs []*CommentGroup)
type Label ¶
type Label interface {
Node
// contains filtered or unexported methods
}
A Label is any production that can be used as a LHS label.
type LetClause ¶ added in v0.2.0
type LetClause struct {
Let token.Pos
Ident *Ident
Equal token.Pos
Expr Expr
// contains filtered or unexported fields
}
A LetClause node represents a let clause in a comprehension.
func (*LetClause) AddComment ¶ added in v0.2.0
func (c *LetClause) AddComment(cg *CommentGroup)
func (*LetClause) SetComments ¶ added in v0.2.0
func (c *LetClause) SetComments(cgs []*CommentGroup)
type ListComprehension ¶
type ListComprehension struct {
Lbrack token.Pos // position of "["
Expr Expr
Clauses []Clause // Feed or Guard (TODO let)
Rbrack token.Pos // position of "]"
// contains filtered or unexported fields
}
A ListComprehension node represents as list comprehension.
func (*ListComprehension) AddComment ¶
func (c *ListComprehension) AddComment(cg *CommentGroup)
func (*ListComprehension) SetComments ¶ added in v0.0.10
func (c *ListComprehension) SetComments(cgs []*CommentGroup)
type ListLit ¶
type ListLit struct {
Lbrack token.Pos // position of "["
// TODO: change to embedding or similar.
Elts []Expr // list of composite elements; or nil
Rbrack token.Pos // position of "]"
// contains filtered or unexported fields
}
A ListLit node represents a literal list.
func NewList ¶ added in v0.0.14
func NewList(exprs ...Expr) *ListLit
NewList creates a list of Expressions. Useful for ASTs generated by code other than the CUE parser.
func (*ListLit) AddComment ¶
func (c *ListLit) AddComment(cg *CommentGroup)
func (*ListLit) SetComments ¶ added in v0.0.10
func (c *ListLit) SetComments(cgs []*CommentGroup)
type Node ¶
type Node interface {
Pos() token.Pos // position of first character belonging to the node
End() token.Pos // position of first character immediately after the node
// Deprecated: use ast.Comments
Comments() []*CommentGroup
// Deprecated: use ast.AddComment
AddComment(*CommentGroup)
// contains filtered or unexported methods
}
A Node represents any node in the abstract syntax tree.
type Package ¶ added in v0.0.6
type Package struct {
PackagePos token.Pos // position of "package" pseudo-keyword
Name *Ident // package name
// contains filtered or unexported fields
}
A Package represents a package clause.
func (*Package) AddComment ¶ added in v0.0.6
func (c *Package) AddComment(cg *CommentGroup)
func (*Package) SetComments ¶ added in v0.0.10
func (c *Package) SetComments(cgs []*CommentGroup)
type ParenExpr ¶
type ParenExpr struct {
Lparen token.Pos // position of "("
X Expr // parenthesized expression
Rparen token.Pos // position of ")"
// contains filtered or unexported fields
}
A ParenExpr node represents a parenthesized expression.
func (*ParenExpr) AddComment ¶
func (c *ParenExpr) AddComment(cg *CommentGroup)
func (*ParenExpr) SetComments ¶ added in v0.0.10
func (c *ParenExpr) SetComments(cgs []*CommentGroup)
type SelectorExpr ¶
type SelectorExpr struct {
X Expr // expression
Sel Label // field selector
// contains filtered or unexported fields
}
A SelectorExpr node represents an expression followed by a selector.
func (*SelectorExpr) AddComment ¶
func (c *SelectorExpr) AddComment(cg *CommentGroup)
func (*SelectorExpr) SetComments ¶ added in v0.0.10
func (c *SelectorExpr) SetComments(cgs []*CommentGroup)
type SliceExpr ¶
type SliceExpr struct {
X Expr // expression
Lbrack token.Pos // position of "["
Low Expr // begin of slice range; or nil
High Expr // end of slice range; or nil
Rbrack token.Pos // position of "]"
// contains filtered or unexported fields
}
An SliceExpr node represents an expression followed by slice indices.
func (*SliceExpr) AddComment ¶
func (c *SliceExpr) AddComment(cg *CommentGroup)
func (*SliceExpr) SetComments ¶ added in v0.0.10
func (c *SliceExpr) SetComments(cgs []*CommentGroup)
type StructLit ¶
type StructLit struct {
Lbrace token.Pos // position of "{"
Elts []Decl // list of elements; or nil
Rbrace token.Pos // position of "}"
// contains filtered or unexported fields
}
A StructLit node represents a literal struct.
func NewStruct ¶ added in v0.1.0
func NewStruct(fields ...interface{}) *StructLit
NewStruct creates a struct from the given fields.
A field is either a *Field, an *Elipsis, *LetClause, a *CommentGroup, or a Label, optionally followed by a a token.OPTION to indicate the field is optional, optionally followed by a token.ISA to indicate the field is a definition followed by an expression for the field value.
It will panic if a values not matching these patterns are given. Useful for ASTs generated by code other than the CUE parser.
func (*StructLit) AddComment ¶
func (c *StructLit) AddComment(cg *CommentGroup)
func (*StructLit) SetComments ¶ added in v0.0.10
func (c *StructLit) SetComments(cgs []*CommentGroup)
type TemplateLabel
deprecated
type TemplateLabel struct {
Langle token.Pos
Ident *Ident
Rangle token.Pos
// contains filtered or unexported fields
}
A TemplateLabel represents a field template declaration in a struct.
Deprecated: use square bracket notation through ListLit.
func (*TemplateLabel) AddComment ¶
func (c *TemplateLabel) AddComment(cg *CommentGroup)
func (*TemplateLabel) SetComments ¶ added in v0.0.10
func (c *TemplateLabel) SetComments(cgs []*CommentGroup)
type UnaryExpr ¶
type UnaryExpr struct {
OpPos token.Pos // position of Op
Op token.Token // operator
X Expr // operand
// contains filtered or unexported fields
}
A UnaryExpr node represents a unary expression.
func (*UnaryExpr) AddComment ¶
func (c *UnaryExpr) AddComment(cg *CommentGroup)
func (*UnaryExpr) SetComments ¶ added in v0.0.10
func (c *UnaryExpr) SetComments(cgs []*CommentGroup)
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