A set of constants for precedence-based expression parsing. Non-operators have lowest precedence, followed by operators starting with precedence 1 up to unary operators. The highest precedence serves as "catch-all" precedence for selector, indexing, and other operator and delimiter tokens.
const (
LowestPrec = lowestPrec
UnaryPrec = unaryPrec
HighestPrec = highestPrec
)
NoPos is the zero value for Pos; there is no file and line information associated with it, and NoPos().IsValid() is false. NoPos is always smaller than any other Pos value. The corresponding Position value for NoPos is the zero value for Position.
var NoPos = Pos{}
A File has a name, size, and line offset table.
type File struct {
// contains filtered or unexported fields
}
func NewFile(filename string, deprecatedBase, size int) *File
NewFile returns a new file with the given OS file name. The size provides the size of the whole file.
The second argument is deprecated. It has no effect.
func (f *File) AddLine(offset int)
AddLine adds the line offset for a new line. The line offset must be larger than the offset for the previous line and smaller than the file size; otherwise the line offset is ignored.
func (f *File) AddLineInfo(offset int, filename string, line int)
AddLineInfo adds alternative file and line number information for a given file offset. The offset must be larger than the offset for the previously added alternative line info and smaller than the file size; otherwise the information is ignored.
AddLineInfo is typically used to register alternative position information for //line filename:line comments in source files.
func (f *File) Base() int
Base returns the base offset of file f as passed to NewFile.
Deprecated: this method just returns the (deprecated) second argument passed to NewFile.
func (f *File) Line(p Pos) int
Line returns the line number for the given file position p; p must be a Pos value in that file or NoPos.
func (f *File) LineCount() int
LineCount returns the number of lines in file f.
func (f *File) MergeLine(line int)
MergeLine merges a line with the following line. It is akin to replacing the newline character at the end of the line with a space (to not change the remaining offsets). To obtain the line number, consult e.g. Position.Line. MergeLine will panic if given an invalid line number.
func (f *File) Name() string
Name returns the file name of file f as registered with AddFile.
func (f *File) Offset(p Pos) int
Offset returns the offset for the given file position p; p must be a valid Pos value in that file. f.Offset(f.Pos(offset)) == offset.
func (f *File) Pos(offset int, rel RelPos) Pos
Pos returns the Pos value for the given file offset; the offset must be <= f.Size(). f.Pos(f.Offset(p)) == p.
func (f *File) Position(p Pos) (pos Position)
Position returns the Position value for the given file position p. Calling f.Position(p) is equivalent to calling f.PositionFor(p, true).
func (f *File) PositionFor(p Pos, adjusted bool) (pos Position)
PositionFor returns the Position value for the given file position p. If adjusted is set, the position may be adjusted by position-altering //line comments; otherwise those comments are ignored. p must be a Pos value in f or NoPos.
func (f *File) SetLines(lines []int) bool
SetLines sets the line offsets for a file and reports whether it succeeded. The line offsets are the offsets of the first character of each line; for instance for the content "ab\nc\n" the line offsets are {0, 3}. An empty file has an empty line offset table. Each line offset must be larger than the offset for the previous line and smaller than the file size; otherwise SetLines fails and returns false. Callers must not mutate the provided slice after SetLines returns.
func (f *File) SetLinesForContent(content []byte)
SetLinesForContent sets the line offsets for the given file content. It ignores position-altering //line comments.
func (f *File) Size() int
Size returns the size of file f as passed to NewFile.
Pos is a compact encoding of a source position within a file, as well as relative positioning information. It can be converted into a Position for a more convenient, but much larger, representation.
type Pos struct {
// contains filtered or unexported fields
}
func (p Pos) Add(n int) Pos
Add creates a new position relative to the p offset by n.
func (p Pos) Before(q Pos) bool
func (p Pos) Column() int
func (p Pos) File() *File
File returns the file that contains the position p or nil if there is no such file (for instance for p == NoPos).
func (p Pos) Filename() string
func (p Pos) HasRelPos() bool
HasRelPos repors whether p has a relative position.
func (p Pos) IsNewline() bool
IsNewline reports whether the relative information suggests this node should be printed on a new lien.
func (p Pos) IsValid() bool
IsValid reports whether the position is valid.
func (p Pos) Line() int
func (p Pos) Offset() int
Offset reports the byte offset relative to the file.
func (p Pos) Position() Position
func (p Pos) RelPos() RelPos
func (p Pos) String() string
func (p Pos) WithRel(rel RelPos) Pos
Position describes an arbitrary source position including the file, line, and column location. A Position is valid if the line number is > 0.
type Position struct {
Filename string // filename, if any
Offset int // offset, starting at 0
Line int // line number, starting at 1
Column int // column number, starting at 1 (byte count)
}
func (pos *Position) IsValid() bool
IsValid reports whether the position is valid.
func (pos Position) String() string
String returns a string in one of several forms:
file:line:column valid position with file name line:column valid position without file name file invalid position with file name - invalid position without file name
RelPos indicates the relative position of token to the previous token.
type RelPos int
const (
// NoRelPos indicates no relative position is specified.
NoRelPos RelPos = iota
// Elided indicates that the token for which this position is defined is
// not rendered at all.
Elided
// NoSpace indicates there is no whitespace after this token.
NoSpace
// Blank means there is horizontal space after this token.
Blank
// Newline means there is a single newline after this token.
Newline
// NewSection means there are two or more newlines after this token.
NewSection
)
func (p RelPos) Pos() Pos
func (p RelPos) String() string
Token is the set of lexical tokens of the CUE configuration language.
type Token int
The list of tokens.
const (
// Special tokens
ILLEGAL Token = iota
EOF
COMMENT
ATTRIBUTE // @foo(bar,baz=4)
// Identifiers and basic type literals
// (these tokens stand for classes of literals)
IDENT // main, _tmp
INT // 12_345Mi, 0700, 0xdeadbeef, 1.2M
FLOAT // 123.45,
// DURATION // 3m4s TODO
STRING // "abc"
INTERPOLATION // a part of a template string, e.g. `"age: \(`
BOTTOM // _|_
// Operators and delimiters
ADD // +
SUB // -
MUL // *
POW // ^
QUO // /
IQUO // quo
IREM // rem
IDIV // div
IMOD // mod
AND // &
OR // |
LAND // &&
LOR // ||
BIND // =
EQL // ==
LSS // <
GTR // >
NOT // !
ARROW // <-
NEQ // !=
LEQ // <=
GEQ // >=
MAT // =~
NMAT // !~
LPAREN // (
LBRACK // [
LBRACE // {
COMMA // ,
PERIOD // .
ELLIPSIS // ...
RPAREN // )
RBRACK // ]
RBRACE // }
SEMICOLON // ;
COLON // :
OPTION // ?
IF
FOR
IN
LET
FUNC // experimental
TRUE
FALSE
NULL
)
func Lookup(ident string) Token
Lookup maps an identifier to its keyword token or IDENT (if not a keyword).
func (tok Token) IsKeyword() bool
IsKeyword returns true for tokens corresponding to keywords; it returns false otherwise.
func (tok Token) IsLiteral() bool
IsLiteral returns true for tokens corresponding to identifiers and basic type literals; it returns false otherwise.
func (tok Token) IsOperator() bool
IsOperator returns true for tokens corresponding to operators and delimiters; it returns false otherwise.
func (tok Token) Precedence() int
Precedence returns the operator precedence of the binary operator op. If op is not a binary operator, the result is LowestPrecedence.
func (tok Token) String() string
String returns the string corresponding to the token tok. For operators, delimiters, and keywords the string is the actual token character sequence (e.g., for the token ADD, the string is "+"). For all other tokens the string corresponds to the token constant name (e.g. for the token IDENT, the string is "IDENT").