lex

package
v0.9.14 Latest Latest
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 Go to latest Published: Mar 16, 2020 License: BSD-3-Clause Imports: 23 Imported by: 6

Documentation

Overview

Package lex provides all the lexing functions that transform text into lexical tokens, using token types defined in the pi/token package. It also has the basic file source and position / region management functionality.

Index

Constants

This section is empty.

Variables

View Source 
var KiT_Actions = kit.Enums.AddEnum(ActionsN, kit.NotBitFlag, nil)
View Source 
var KiT_MatchPos = kit.Enums.AddEnum(MatchPosN, kit.NotBitFlag, nil)
View Source 
var KiT_Matches = kit.Enums.AddEnum(MatchesN, kit.NotBitFlag, nil)
View Source 
var KiT_Rule = kit.Types.AddType(&Rule{}, RuleProps)
View Source 
var PosErr = Pos{-1, -1}

PosErr represents an error text position (-1 for both line and char) used as a return value for cases where error positions are possible

View Source 
var PosZero = Pos{}

PosZero is the uninitialized zero text position (which is still a valid position)

View Source 
var RegZero = Reg{}

RegZero is the zero region

View Source 
var RuleProps = ki.Props{}

Functions

func DigitVal 

func DigitVal(ch rune) int

func FirstWord added in v0.9.14 

func FirstWord(str string) string

FirstWord returns the first contiguous sequence of purely unicode.IsLetter runes within given string -- skips over any leading non-letters until a letter is found. This does not include numbers -- use FirstWordDigits for that

func FirstWordApostrophe added in v0.9.14 

func FirstWordApostrophe(str string) string

FirstWordApostrophe returns the first contiguous sequence of purely unicode.IsLetter runes. that can also contain an apostrophe *within* the word but not at the end

func FirstWordDigits added in v0.9.14 

func FirstWordDigits(str string) string

FirstWordDigits returns the first contiguous sequence of purely IsLetterOrDigit runes within given string -- skips over any leading non-letters until a *letter* (not digit) is found.

func InnerBracketScope added in v0.9.13 

func InnerBracketScope(str string, brl, brr string) string

InnerBracketScope returns the inner-scope for given bracket type if it is imbalanced -- it is important to do completion based just on that inner scope if that is where the user is at.

func IsDigit 

func IsDigit(ch rune) bool

func IsLetter 

func IsLetter(ch rune) bool

func IsLetterOrDigit added in v0.9.11 

func IsLetterOrDigit(ch rune) bool

func IsWhiteSpace 

func IsWhiteSpace(ch rune) bool

func IsWordBreak added in v0.9.14 

func IsWordBreak(r1, r2 rune) bool

IsWordBreak defines what counts as a word break for the purposes of selecting words r1 is the rune in question, r2 is the rune past r1 in the direction you are moving Pass rune(-1) for r2 if there is no rune past r1

func LastField added in v0.9.13 

func LastField(str string) string

LastField returns the last white-space separated string

func LastScopedString added in v0.9.13 

func LastScopedString(str string) string

LastScopedString returns the last white-space separated, and bracket enclosed string from given string.

func MatchCase added in v0.9.14 

func MatchCase(src, trg string) string

MatchCase uses the source string case (upper / lower) to set corresponding case in target string, returning that string.

func OpenFileBytes added in v0.9.11 

func OpenFileBytes(fname string) ([]byte, error)

OpenFileBytes returns bytes in given file, and logs any errors as well

func PrintError 

func PrintError(w io.Writer, err error)

PrintError is a utility function that prints a list of errors to w, one error per line, if the err parameter is an ErrorList. Otherwise it prints the err string.

func RunesFromBytes added in v0.5.5 

func RunesFromBytes(b []byte) [][]rune

RunesFromBytes returns the lines of runes from a basic byte array

func RunesFromString added in v0.5.5 

func RunesFromString(str string) [][]rune

RunesFromString returns the lines of runes from a string (more efficient than converting to bytes)

func TrimLeftToAlpha added in v0.9.13 

func TrimLeftToAlpha(nm string) string

TrimLeftToAlpha returns string without any leading non-alpha runes

Types

type Actions 

type Actions int

Actions are lexing actions to perform 

const (
	// Next means advance input position to the next character(s) after the matched characters
	Next Actions = iota

	// Name means read in an entire name, which is letters, _ and digits after first letter
	// position will be advanced to just after
	Name

	// Number means read in an entire number -- the token type will automatically be
	// set to the actual type of number that was read in, and position advanced to just after
	Number

	// Quoted means read in an entire string enclosed in quote delimeter
	// that is present at current position, with proper skipping of escaped.
	// Position advanced to just after
	Quoted

	// QuotedRaw means read in an entire string enclosed in quote delimeter
	// that is present at start position, with proper skipping of escaped.
	// Position advanced to just after.
	// Raw version supports multi-line and includes CR etc at end of lines (e.g., back-tick
	// in various languages)
	QuotedRaw

	// EOL means read till the end of the line (e.g., for single-line comments)
	EOL

	// ReadUntil reads until string(s) in the Until field are found,
	// or until the EOL if none are found
	ReadUntil

	// PushState means push the given state value onto the state stack
	PushState

	// PopState means pop given state value off the state stack
	PopState

	// SetGuestLex means install the Name (must be a prior action) as the guest
	// lexer -- it will take over lexing until PopGuestLex is called
	SetGuestLex

	// PopGuestLex removes the current guest lexer and returns to the original
	// language lexer
	PopGuestLex

	ActionsN
)

The lexical acts

func (*Actions) FromString 

func (i *Actions) FromString(s string) error

func (Actions) MarshalJSON 

func (ev Actions) MarshalJSON() ([]byte, error)

func (Actions) String 

func (i Actions) String() string

func (*Actions) UnmarshalJSON 

func (ev *Actions) UnmarshalJSON(b []byte) error

type EosPos added in v0.5.5 

type EosPos []int

EosPos is a line of EOS token positions, always sorted low-to-high

func (EosPos) FindGt added in v0.5.5 

func (ep EosPos) FindGt(ch int) int

FindGt returns any pos value greater than given token pos, -1 if none

func (EosPos) FindGtEq added in v0.5.5 

func (ep EosPos) FindGtEq(ch int) int

FindGtEq returns any pos value greater than or equal to given token pos, -1 if none

type Error 

type Error struct {
	Pos      Pos    `desc:"position where the error occurred in the source"`
	Filename string `desc:"full filename with path"`
	Msg      string `desc:"brief error message"`
	Src      string `desc:"line of source where error was"`
	Rule     ki.Ki  `desc:"lexer or parser rule that emitted the error"`
}

In an ErrorList, an error is represented by an *Error. The position Pos, if valid, points to the beginning of the offending token, and the error condition is described by Msg.

func (Error) Error 

func (e Error) Error() string

Error implements the error interface -- gives the minimal version of error string

func (Error) Report added in v0.5.5 

func (e Error) Report(basepath string, showSrc, showRule bool) string

Report provides customizable output options for viewing errors: - basepath if non-empty shows filename relative to that path. - showSrc shows the source line on a second line -- truncated to 30 chars around err - showRule prints the rule name

type ErrorList 

type ErrorList []*Error

ErrorList is a list of *Errors. The zero value for an ErrorList is an empty ErrorList ready to use.

func (*ErrorList) Add 

func (p *ErrorList) Add(pos Pos, fname, msg string, srcln string, rule ki.Ki) *Error

Add adds an Error with given position and error message to an ErrorList.

func (ErrorList) Err 

func (p ErrorList) Err() error

Err returns an error equivalent to this error list. If the list is empty, Err returns nil.

func (ErrorList) Error 

func (p ErrorList) Error() string

An ErrorList implements the error interface.

func (ErrorList) Len 

func (p ErrorList) Len() int

ErrorList implements the sort Interface.

func (ErrorList) Less 

func (p ErrorList) Less(i, j int) bool

func (*ErrorList) RemoveMultiples 

func (p *ErrorList) RemoveMultiples()

RemoveMultiples sorts an ErrorList and removes all but the first error per line.

func (ErrorList) Report added in v0.5.5 

func (p ErrorList) Report(maxN int, basepath string, showSrc, showRule bool) string

Report returns all (or up to maxN if > 0) errors in the list in one string with customizable output options for viewing errors: - basepath if non-empty shows filename relative to that path. - showSrc shows the source line on a second line -- truncated to 30 chars around err - showRule prints the rule name

func (*ErrorList) Reset 

func (p *ErrorList) Reset()

Reset resets an ErrorList to no errors.

func (ErrorList) Sort 

func (p ErrorList) Sort()

Sort sorts an ErrorList. *Error entries are sorted by position, other errors are sorted by error message, and before any *Error entry.

func (ErrorList) Swap 

func (p ErrorList) Swap(i, j int)

type File 

type File struct {
	Filename   string            `desc:"the current file being lex'd"`
	Sup        filecat.Supported `desc:"the supported file type, if supported (typically only supported files are processed)"`
	BasePath   string            `desc:"base path for reporting file names -- this must be set externally e.g., by gide for the project root path"`
	Lexs       []Line            `desc:"lex'd version of the lines -- allocated to size of Lines"`
	Comments   []Line            `` /* 148-byte string literal not displayed */
	LastStacks []Stack           `desc:"stack present at the end of each line -- needed for contextualizing line-at-time lexing while editing"`
	EosPos     []EosPos          `desc:"token positions per line for the EOS (end of statement) tokens -- very important for scoping top-down parsing"`
	Lines      [][]rune          `desc:"contents of the file as lines of runes"`
}

File contains the contents of the file being parsed -- all kept in memory, and represented by Line as runes, so that positions in the file are directly convertible to indexes in Lines structure

func (*File) AllocLines 

func (fl *File) AllocLines()

AllocLines allocates the data per line: lex outputs and stack. We reset state so stale state is not hanging around.

func (*File) EnsureFinalEos added in v0.5.5 

func (fl *File) EnsureFinalEos(ln int)

EnsureFinalEos makes sure that the given line ends with an EOS (if it has tokens). Used for line-at-time parsing just to make sure it matches even if you haven't gotten to the end etc.

func (*File) InitFromLine added in v0.5.5 

func (fl *File) InitFromLine(sfl *File, ln int) bool

InitFromLine initializes from one line of source file

func (*File) InitFromString added in v0.5.5 

func (fl *File) InitFromString(str string, fname string, sup filecat.Supported) bool

InitFromString initializes from given string. Returns false if string is empty

func (*File) InsertEos added in v0.5.5 

func (fl *File) InsertEos(cp Pos) Pos

InsertEos inserts an EOS just after the given token position (e.g., cp = last token in line)

func (*File) IsLexPosValid 

func (fl *File) IsLexPosValid(pos Pos) bool

IsLexPosValid returns true if given lexical token position is valid

func (*File) LexAt 

func (fl *File) LexAt(cp Pos) *Lex

LexAt returns Lex item at given position, with no checking

func (*File) LexAtSafe 

func (fl *File) LexAtSafe(cp Pos) Lex

LexAtSafe returns the Lex item at given position, or last lex item if beyond end

func (*File) LexLine 

func (fl *File) LexLine(ln int) Line

LexLine returns the lexing output for given line, combining comments and all other tokens and allocating new memory using clone

func (*File) LexTagSrc 

func (fl *File) LexTagSrc() string

LexTagSrc returns the lex'd tagged source for entire source

func (*File) LexTagSrcLn 

func (fl *File) LexTagSrcLn(ln int) string

LexTagSrcLn returns the lex'd tagged source line for given line

func (*File) LinesDeleted 

func (fl *File) LinesDeleted(stln, edln int)

LinesDeleted deletes lines -- called e.g., by giv.TextBuf to sync the markup with ongoing edits

func (*File) LinesInserted 

func (fl *File) LinesInserted(stln, nlns int)

LinesInserted inserts new lines -- called e.g., by giv.TextBuf to sync the markup with ongoing edits

func (*File) NLines 

func (fl *File) NLines() int

NLines returns the number of lines in source

func (*File) NTokens 

func (fl *File) NTokens(ln int) int

NTokens returns number of lex tokens for given line

func (*File) NextEos added in v0.5.5 

func (fl *File) NextEos(stpos Pos, depth int) (Pos, bool)

NextEos finds the next EOS position at given depth, false if none

func (*File) NextEosAnyDepth added in v0.5.5 

func (fl *File) NextEosAnyDepth(stpos Pos) (Pos, bool)

NextEosAnyDepth finds the next EOS at any depth

func (*File) NextTokenPos 

func (fl *File) NextTokenPos(pos Pos) (Pos, bool)

NextTokenPos returns the next token position, false if at end of tokens

func (*File) OpenFile added in v0.5.5 

func (fl *File) OpenFile(fname string) error

OpenFile sets source to be parsed from given filename

func (*File) PrevDepth 

func (fl *File) PrevDepth(ln int) int

PrevDepth returns the depth of the token immediately prior to given line

func (*File) PrevStack 

func (fl *File) PrevStack(ln int) Stack

PrevStack returns the stack from the previous line

func (*File) PrevTokenPos 

func (fl *File) PrevTokenPos(pos Pos) (Pos, bool)

PrevTokenPos returns the previous token position, false if at end of tokens

func (*File) RegSrc 

func (fl *File) RegSrc(reg Reg) string

RegSrc returns the source (as a string) for given region

func (*File) ReplaceEos added in v0.5.5 

func (fl *File) ReplaceEos(cp Pos)

ReplaceEos replaces given token with an EOS

func (*File) SetBytes added in v0.9.11 

func (fl *File) SetBytes(txt []byte)

SetBytes sets source to be parsed from given bytes

func (*File) SetLine 

func (fl *File) SetLine(ln int, lexs, comments Line, stack Stack)

SetLine sets the line data from the lexer -- does a clone to keep the copy

func (*File) SetLineSrc added in v0.9.11 

func (fl *File) SetLineSrc(ln int, txt []rune) bool

SetLineSrc sets source runes from given line of runes. Returns false if out of range.

func (*File) SetSrc 

func (fl *File) SetSrc(src [][]rune, fname, basepath string, sup filecat.Supported)

SetSrc sets the source to given content, and alloc Lexs -- if basepath is empty then it is set to the path for the filename

func (*File) SrcLine added in v0.5.5 

func (fl *File) SrcLine(ln int) string

SrcLine returns given line of source, as a string, or "" if out of range

func (*File) Token 

func (fl *File) Token(pos Pos) token.KeyToken

Token gets lex token at given Pos (Ch = token index)

func (*File) TokenMapReg 

func (fl *File) TokenMapReg(reg Reg) TokenMap

TokenMapReg creates a TokenMap of tokens in region, including their Cat and SubCat levels -- err's on side of inclusiveness -- used for optimizing token matching

func (*File) TokenRegSrc 

func (fl *File) TokenRegSrc(reg Reg) string

TokenRegSrc returns the source code associated with the given token region

func (*File) TokenSrc 

func (fl *File) TokenSrc(pos Pos) []rune

TokenSrc gets source runes for given token position

func (*File) TokenSrcPos 

func (fl *File) TokenSrcPos(pos Pos) Reg

TokenSrcPos returns source reg associated with lex token at given token position

func (*File) TokenSrcReg 

func (fl *File) TokenSrcReg(reg Reg) Reg

TokenSrcReg translates a region of tokens into a region of source

func (*File) ValidTokenPos 

func (fl *File) ValidTokenPos(pos Pos) (Pos, bool)

ValidTokenPos returns the next valid token position starting at given point, false if at end of tokens

type LangLexer 

type LangLexer interface {
	// LexerByName returns the top-level lex.Rule for given language (case invariant lookup)
	LexerByName(lang string) *Rule
}

LangLexer looks up lexer for given language -- impl in parent pi package so we need the interface 

var TheLangLexer LangLexer

TheLangLexer is the instance of LangLexer interface used to lookup lexers for languages -- is set in pi/langs.go

type Lex 

type Lex struct {
	Tok  token.KeyToken `` /* 261-byte string literal not displayed */
	St   int            `desc:"start rune index within original source line for this token"`
	Ed   int            `desc:"end rune index within original source line for this token (exclusive -- ends one before this)"`
	Time nptime.Time    `` /* 129-byte string literal not displayed */
}

Lex represents a single lexical element, with a token, and start and end rune positions within a line of a file. Critically it also contains the nesting depth computed from all the parens, brackets, braces. Todo: also support XML < > </ > tag depth.

func NewLex 

func NewLex(tok token.KeyToken, st, ed int) Lex

func (*Lex) ContainsPos 

func (lx *Lex) ContainsPos(pos int) bool

ContainsPos returns true if the Lex element contains given character position

func (*Lex) Now added in v0.9.14 

func (lx *Lex) Now()

Now sets the time stamp to now

func (*Lex) OverlapsReg 

func (lx *Lex) OverlapsReg(or Lex) bool

OverlapsReg returns true if the two regions overlap

func (*Lex) Region added in v0.5.5 

func (lx *Lex) Region(ln int) Reg

Region returns the region for this lexical element, at given line

func (*Lex) Src added in v0.9.14 

func (lx *Lex) Src(src []rune) []rune

Src returns the rune source for given lex item (does no validity checking)

func (*Lex) String 

func (lx *Lex) String() string

String satisfies the fmt.Stringer interface

type Lexer 

type Lexer interface {
	ki.Ki

	// Compile performs any one-time compilation steps on the rule
	Compile(ls *State) bool

	// Validate checks for any errors in the rules and issues warnings,
	// returns true if valid (no err) and false if invalid (errs)
	Validate(ls *State) bool

	// Lex tries to apply rule to given input state, returns true if matched, false if not
	Lex(ls *State) *Rule

	// AsLexRule returns object as a lex.Rule
	AsLexRule() *Rule
}

Lexer is the interface type for lexers -- likely not necessary except is essential for defining the BaseIface for gui in making new nodes

type Line 

type Line []Lex

Line is one line of Lex'd text

func MergeLines 

func MergeLines(t1, t2 Line) Line

MergeLines merges the two lines of lex regions into a combined list properly ordered by sequence of tags within the line.

func RuneFields added in v0.9.13 

func RuneFields(src []rune) Line

RuneFields returns a Line of Lex's defining the non-white-space "fields" in the given rune string

func (*Line) Add 

func (ll *Line) Add(lx Lex)

Add adds one element to the lex line (just append)

func (*Line) AddLex 

func (ll *Line) AddLex(tok token.KeyToken, st, ed int) *Lex

Add adds one element to the lex line with given params, returns pointer to that new lex

func (*Line) AddSort 

func (ll *Line) AddSort(lx Lex)

AddSort adds a new lex element in sorted order to list, sorted by start position, and if at the same start position, then sorted *decreasing* by end position -- this allows outer tags to be processed before inner tags which fits a stack-based tag markup logic.

func (*Line) AtPos added in v0.9.13 

func (ll *Line) AtPos(pos int) *Lex

AtPos returns the Lex in place for given position, or nil if none

func (*Line) Clone 

func (ll *Line) Clone() Line

Clone returns a new copy of the line

func (*Line) DeleteIdx added in v0.9.14 

func (ll *Line) DeleteIdx(idx int)

DeleteIdx deletes at given index

func (*Line) DeleteToken added in v0.9.14 

func (ll *Line) DeleteToken(tok token.Tokens)

DeleteToken deletes a specific token type from list

func (*Line) Insert 

func (ll *Line) Insert(idx int, lx Lex)

Insert inserts one element to the lex line at given point

func (*Line) NonCodeWords added in v0.9.14 

func (ll *Line) NonCodeWords(src []rune) Line

NonCodeWords returns a Line of white-space separated word tokens in given tagged source that ignores token.IsCode token regions -- i.e., the "regular" words present in the source line -- this is useful for things like spell checking or manual parsing.

func (*Line) RuneStrings added in v0.9.13 

func (ll *Line) RuneStrings(rstr []rune) []string

RuneStrings returns array of strings for Lex regions defined in Line, for given rune source string

func (*Line) Sort 

func (ll *Line) Sort()

Sort sorts the lex elements by starting pos, and ending pos *decreasing* if a tie

func (*Line) String 

func (ll *Line) String() string

String satisfies the fmt.Stringer interface

func (*Line) Strings added in v0.9.14 

func (ll *Line) Strings(src []rune) []string

Strings returns a slice of strings for each of the Lex items in given rune src split by Line Lex's. Returns nil if Line empty.

func (*Line) TagSrc 

func (ll *Line) TagSrc(src []rune) string

TagSrc returns the token-tagged source

type MatchPos 

type MatchPos int

MatchPos are special positions for a match to occur 

const (
	// AnyPos matches at any position
	AnyPos MatchPos = iota

	// StartOfLine matches at start of line
	StartOfLine

	// EndOfLine matches at end of line
	EndOfLine

	// MiddleOfLine matches not at the start or end
	MiddleOfLine

	// StartOfWord matches at start of word
	StartOfWord

	// EndOfWord matches at end of word
	EndOfWord

	// MiddleOfWord matches not at the start or end
	MiddleOfWord

	MatchPosN
)

Matching position rules

func (*MatchPos) FromString 

func (i *MatchPos) FromString(s string) error

func (MatchPos) MarshalJSON 

func (ev MatchPos) MarshalJSON() ([]byte, error)

func (MatchPos) String 

func (i MatchPos) String() string

func (*MatchPos) UnmarshalJSON 

func (ev *MatchPos) UnmarshalJSON(b []byte) error

type Matches 

type Matches int

Matches are what kind of lexing matches to make 

const (
	// String means match a specific string as given in the rule
	// Note: this only looks for the string with no constraints on
	// what happens after this string -- use StrName to match entire names
	String Matches = iota

	// StrName means match a specific string that is a complete alpha-numeric
	// string (including underbar _) with some other char at the end
	// must use this for all keyword matches to ensure that it isn't just
	// the start of a longer name
	StrName

	// Match any letter, including underscore
	Letter

	// Match digit 0-9
	Digit

	// Match any white space (space, tab) -- input is already broken into lines
	WhiteSpace

	// CurState means match current state value set by a PushState action, using String value in rule
	// all CurState cases must generally be first in list of rules so they can preempt
	// other rules when the state is active
	CurState

	// AnyRune means match any rune -- use this as the last condition where other terminators
	// come first!
	AnyRune

	MatchesN
)

Matching rules

func (*Matches) FromString 

func (i *Matches) FromString(s string) error

func (Matches) MarshalJSON 

func (ev Matches) MarshalJSON() ([]byte, error)

func (Matches) String 

func (i Matches) String() string

func (*Matches) UnmarshalJSON 

func (ev *Matches) UnmarshalJSON(b []byte) error

type PassTwo 

type PassTwo struct {
	DoEos     bool               `desc:"should we perform EOS detection on this type of file?"`
	Eol       bool               `desc:"use end-of-line as a default EOS, if nesting depth is same as start of line (python) -- see also EolToks"`
	Semi      bool               `desc:"replace all semicolons with EOS to keep it consistent (C, Go..)"`
	Backslash bool               `desc:"use backslash as a line continuer (python)"`
	RBraceEos bool               `` /* 167-byte string literal not displayed */
	EolToks   token.KeyTokenList `desc:"specific tokens to recognize at the end of a line that trigger an EOS (Go)"`
}

PassTwo performs second pass(s) through the lexicalized version of the source, computing nesting depth for every token once and for all -- this is essential for properly matching tokens and also for colorization in syntax highlighting. Optionally, a subsequent pass finds end-of-statement (EOS) tokens, which are essential for parsing to first break the source down into statement-sized chunks. A separate list of EOS token positions is maintained for very fast access.

func (*PassTwo) EosDetect 

func (pt *PassTwo) EosDetect(ts *TwoState)

Perform EOS detection

func (*PassTwo) EosDetectPos added in v0.5.5 

func (pt *PassTwo) EosDetectPos(ts *TwoState, pos Pos, nln int)

Perform EOS detection at given starting position, for given number of lines

func (*PassTwo) Error 

func (pt *PassTwo) Error(ts *TwoState, msg string)

Error adds an passtwo error at given position

func (*PassTwo) HasErrs 

func (pt *PassTwo) HasErrs(ts *TwoState) bool

HasErrs reports if there are errors in eosing process

func (*PassTwo) MismatchError 

func (pt *PassTwo) MismatchError(ts *TwoState, tok token.Tokens)

MismatchError reports a mismatch for given type of parentheses / bracket

func (*PassTwo) NestDepth 

func (pt *PassTwo) NestDepth(ts *TwoState)

Perform nesting depth computation

func (*PassTwo) NestDepthLine 

func (pt *PassTwo) NestDepthLine(line Line, initDepth int)

Perform nesting depth computation on only one line, starting at given initial depth -- updates the given line

func (*PassTwo) PopNest 

func (pt *PassTwo) PopNest(ts *TwoState, tok token.Tokens)

PopNest attempts to pop given token off of nesting stack, generating error if it mismatches

func (*PassTwo) PushNest 

func (pt *PassTwo) PushNest(ts *TwoState, tok token.Tokens)

PushNest pushes a nesting left paren / bracket onto stack

type Pos 

type Pos struct {
	Ln int
	Ch int
}

Pos is a position within the source file -- it is recorded always in 0, 0 offset positions, but is converted into 1,1 offset for public consumption Ch positions are always in runes, not bytes. Also used for lex token indexes.

func (*Pos) IsLess 

func (ps *Pos) IsLess(cmp Pos) bool

IsLess returns true if receiver position is less than given comparison

func (Pos) String 

func (ps Pos) String() string

String satisfies the fmt.Stringer interferace

type Reg 

type Reg struct {
	St Pos `desc:"starting position of region"`
	Ed Pos `desc:"ending position of region"`
}

Reg is a contiguous region within the source file

func (Reg) Contains added in v0.5.5 

func (tr Reg) Contains(ps Pos) bool

Contains returns true if region contains position

func (Reg) IsNil 

func (tr Reg) IsNil() bool

IsNil checks if the region is empty, because the start is after or equal to the end

type Rule 

type Rule struct {
	ki.Node
	Off       bool             `desc:"disable this rule -- useful for testing and exploration"`
	Desc      string           `desc:"description / comments about this rule"`
	Token     token.Tokens     `desc:"the token value that this rule generates -- use None for non-terminals"`
	Match     Matches          `desc:"the lexical match that we look for to engage this rule"`
	Pos       MatchPos         `desc:"position where match can occur"`
	String    string           `desc:"if action is LexMatch, this is the string we match"`
	Offset    int              `desc:"offset into the input to look for a match: 0 = current char, 1 = next one, etc"`
	SizeAdj   int              `` /* 151-byte string literal not displayed */
	Acts      []Actions        `desc:"the action(s) to perform, in order, if there is a match -- these are performed prior to iterating over child nodes"`
	Until     string           `` /* 260-byte string literal not displayed */
	PushState string           `desc:"the state to push if our action is PushState -- note that State matching is on String, not this value"`
	NameMap   bool             `` /* 336-byte string literal not displayed */
	MatchLen  int              `view:"-" json:"-" xml:"-" desc:"length of source that matched -- if Next is called, this is what will be skipped to"`
	NmMap     map[string]*Rule `inactive:"+" json:"-" xml:"-" desc:"NameMap lookup map -- created during Compile"`
}

lex.Rule operates on the text input to produce the lexical tokens.

Lexing is done line-by-line -- you must push and pop states to coordinate across multiple lines, e.g., for multi-line comments.

There is full access to entire line and you can decide based on future (offset) characters.

In general it is best to keep lexing as simple as possible and leave the more complex things for the parsing step.

func (*Rule) AsLexRule 

func (lr *Rule) AsLexRule() *Rule

func (*Rule) BaseIface 

func (lr *Rule) BaseIface() reflect.Type

func (*Rule) Compile added in v0.5.5 

func (lr *Rule) Compile(ls *State) bool

Compile performs any one-time compilation steps on the rule returns false if there are any problems.

func (*Rule) CompileAll added in v0.5.5 

func (lr *Rule) CompileAll(ls *State) bool

CompileAll is called on the top-level Rule to compile all nodes. returns true if everything is ok

func (*Rule) CompileNameMap added in v0.5.5 

func (lr *Rule) CompileNameMap(ls *State) bool

CompileNameMap compiles name map -- returns false if there are problems.

func (*Rule) ComputeMatchLen added in v0.5.5 

func (lr *Rule) ComputeMatchLen(ls *State)

ComputeMatchLen computes MatchLen based on match type

func (*Rule) DoAct 

func (lr *Rule) DoAct(ls *State, act Actions, tok *token.KeyToken)

DoAct performs given action

func (*Rule) Find 

func (lr *Rule) Find(find string) []*Rule

Find looks for rules in the tree that contain given string in String or Name fields

func (*Rule) IsMatch 

func (lr *Rule) IsMatch(ls *State) bool

IsMatch tests if the rule matches for current input state, returns true if so, false if not

func (*Rule) IsMatchPos 

func (lr *Rule) IsMatchPos(ls *State) bool

IsMatchPos tests if the rule matches position

func (*Rule) Lex 

func (lr *Rule) Lex(ls *State) *Rule

Lex tries to apply rule to given input state, returns lowest-level rule that matched, nil if none

func (*Rule) LexStart 

func (lr *Rule) LexStart(ls *State) *Rule

LexStart is called on the top-level lex node to start lexing process for one step

func (*Rule) TargetLen 

func (lr *Rule) TargetLen(ls *State) int

TargetLen returns the length of the target including offset

func (*Rule) Validate 

func (lr *Rule) Validate(ls *State) bool

Validate checks for any errors in the rules and issues warnings, returns true if valid (no err) and false if invalid (errs)

func (*Rule) WriteGrammar 

func (lr *Rule) WriteGrammar(writer io.Writer, depth int)

WriteGrammar outputs the lexer rules as a formatted grammar in a BNF-like format it is called recursively

type Stack 

type Stack []string

Stack is the stack for states

func (*Stack) Clone 

func (ss *Stack) Clone() Stack

Clone returns a copy of the stack

func (*Stack) Pop 

func (ss *Stack) Pop() string

Pop takes state off the stack and returns it

func (*Stack) Push 

func (ss *Stack) Push(state string)

Push appends state to stack

func (*Stack) Reset added in v0.5.5 

func (ss *Stack) Reset()

Reset stack

func (*Stack) Top 

func (ss *Stack) Top() string

Top returns the state at the top of the stack

type State 

type State struct {
	Filename  string      `desc:"the current file being lex'd"`
	KeepWS    bool        `desc:"if true, record whitespace tokens -- else ignore"`
	Src       []rune      `desc:"the current line of source being processed"`
	Lex       Line        `desc:"the lex output for this line"`
	Comments  Line        `desc:"the comments output for this line -- kept separately"`
	Pos       int         `desc:"the current rune char position within the line"`
	Ln        int         `desc:"the line within overall source that we're operating on (0 indexed)"`
	Ch        rune        `desc:"the current rune read by NextRune"`
	Stack     Stack       `desc:"state stack"`
	LastName  string      `desc:"the last name that was read"`
	GuestLex  *Rule       `desc:"a guest lexer that can be installed for managing a different language type, e.g., quoted text in markdown files"`
	SaveStack Stack       `desc:"copy of stack at point when guest lexer was installed -- restore when popped"`
	Time      nptime.Time `desc:"time stamp for lexing -- set at start of new lex process"`
	Errs      ErrorList   `desc:"any error messages accumulated during lexing specifically"`
}

lex.State is the state maintained for lexing

func (*State) Add 

func (ls *State) Add(tok token.KeyToken, st, ed int)

Add adds a lex token for given region -- merges with prior if same

func (*State) AtEol 

func (ls *State) AtEol() bool

AtEol returns true if current position is at end of line

func (*State) CurRune 

func (ls *State) CurRune() bool

CurRune reads the current rune into Ch and returns false if at end of line

func (*State) CurState 

func (ls *State) CurState() string

CurState returns the current state

func (*State) Error 

func (ls *State) Error(pos int, msg string, rule *Rule)

Error adds a lexing error at given position

func (*State) Init 

func (ls *State) Init()

Init initializes the state at start of parsing

func (*State) LineString 

func (ls *State) LineString() string

LineString returns the current lex output as tagged source

func (*State) MatchState added in v0.5.5 

func (ls *State) MatchState(st string) bool

MatchState returns true if the current state matches the string

func (*State) Next 

func (ls *State) Next(inc int) bool

Next moves to next position using given increment in source line -- returns false if at end

func (*State) NextRune 

func (ls *State) NextRune() bool

NextRune reads the next rune into Ch and returns false if at end of line

func (*State) NextSrcLine 

func (ls *State) NextSrcLine() string

NextSrcLine returns the next line of text

func (*State) PopState 

func (ls *State) PopState() string

PopState pops state off of stack

func (*State) PushState 

func (ls *State) PushState(st string)

PushState pushes state onto stack

func (*State) ReadEscape 

func (ls *State) ReadEscape(quote rune) bool

ReadEscape parses an escape sequence where rune is the accepted escaped quote. In case of a syntax error, it stops at the offending character (without consuming it) and returns false. Otherwise it returns true.

func (*State) ReadName 

func (ls *State) ReadName()

ReadName reads a standard alpha-numeric_ name -- saves in LastName

func (*State) ReadNameTmp added in v0.5.5 

func (ls *State) ReadNameTmp(off int) string

ReadNameTmp reads a standard alpha-numeric_ name and returns it. Does not update the lexing position -- a "lookahead" name read

func (*State) ReadNumber 

func (ls *State) ReadNumber() token.Tokens

ReadNumber reads a number of any sort, returning the type of the number

func (*State) ReadQuoted 

func (ls *State) ReadQuoted()

func (*State) ReadUntil added in v0.5.5 

func (ls *State) ReadUntil(until string)

ReadUntil reads until given string(s) -- does do depth tracking if looking for a bracket open / close kind of symbol. For multiple "until" string options, separate each by | and use empty to match a single | or || in combination with other options. Terminates at end of line without error

func (*State) Rune 

func (ls *State) Rune(off int) (rune, bool)

Rune gets the rune at given offset from current position, returns false if out of range

func (*State) ScanMantissa 

func (ls *State) ScanMantissa(base int)

func (*State) SetLine 

func (ls *State) SetLine(src []rune)

SetLine sets a new line for parsing and initializes the lex output and pos

func (*State) String 

func (ls *State) String(off, sz int) (string, bool)

String gets the string at given offset and length from current position, returns false if out of range

type TokenMap 

type TokenMap map[token.Tokens]struct{}

TokenMap is a token map, for optimizing token exclusion

func (TokenMap) Has 

func (tm TokenMap) Has(tok token.Tokens) bool

Has returns true if given token is in the map

func (TokenMap) Set 

func (tm TokenMap) Set(tok token.Tokens)

Set sets map for given token

type TwoState 

type TwoState struct {
	Pos       Pos            `desc:"position in lex tokens we're on"`
	Src       *File          `desc:"file that we're operating on"`
	NestStack []token.Tokens `desc:"stack of nesting tokens"`
	Errs      ErrorList      `desc:"any error messages accumulated during lexing specifically"`
}

TwoState is the state maintained for the PassTwo process

func (*TwoState) Error 

func (ts *TwoState) Error(msg string)

Error adds an passtwo error at current position

func (*TwoState) Init 

func (ts *TwoState) Init()

Init initializes state for a new pass -- called at start of NestDepth

func (*TwoState) NestStackStr 

func (ts *TwoState) NestStackStr() string

NestStackStr returns the token stack as strings

func (*TwoState) NextLine 

func (ts *TwoState) NextLine()

NextLine advances to next line

func (*TwoState) SetSrc 

func (ts *TwoState) SetSrc(src *File)

SetSrc sets the source we're operating on

Source Files

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