dsl

Documentation

Overview

Package dsl is the boolean rule-expression engine: lexer, parser (! > && > ||), AST, dive splitting.

Index

• func ContainsDiveToken(input string, isRawArg IsRawArgFunc) bool
• func DefaultIsRawArg(name string) bool
• func HasTopLevelOr(input string, isRawArg IsRawArgFunc) bool
• func RemoveTopLevelLeaves(input string, names map[string]bool, isRawArg IsRawArgFunc) string
• func SplitDive(input string, isRawArg IsRawArgFunc) (container, element string, hasDive bool, err error)
• type And
• type IsRawArgFunc
• type Leaf
• type Node
  • func Parse(input string, isRawArg IsRawArgFunc) (Node, error)
• type Not
• type Or
• type ParseError
  • func (e *ParseError) Error() string

Functions

func ContainsDiveToken

func ContainsDiveToken(input string, isRawArg IsRawArgFunc) bool

ContainsDiveToken reports whether a standalone `dive` leaf appears at any depth.

func DefaultIsRawArg

func DefaultIsRawArg(name string) bool

func HasTopLevelOr

func HasTopLevelOr(input string, isRawArg IsRawArgFunc) bool

HasTopLevelOr reports whether input has a `||` outside parentheses. Lex error yields true: safe to wrap a malformed expr before &&-joining.

func RemoveTopLevelLeaves

func RemoveTopLevelLeaves(input string, names map[string]bool, isRawArg IsRawArgFunc) string

RemoveTopLevelLeaves drops top-level bare-leaf segments whose name (or trimmed source) is in names, re-joining survivors with " && ". Lexer-driven so a separator inside a quoted/raw arg isn't mistaken for structural.

func SplitDive

func SplitDive(input string, isRawArg IsRawArgFunc) (container, element string, hasDive bool, err error)

SplitDive splits on a top-level standalone `dive` into container/element exprs. Malformed dive placement fails closed.

Types

type And

type And struct {
	L, R Node
}

And is logical conjunction: L && R.

type IsRawArgFunc

type IsRawArgFunc func(name string) bool

IsRawArgFunc reports whether a rule reads its argument raw (one arg, commas literal).

type Leaf

type Leaf struct {
	Name string
	Args []string
	Pos  int
}

Leaf is a single rule invocation, e.g. in:a,b,c.

type Node

type Node interface {
	// contains filtered or unexported methods
}

Node is a node in a parsed rule expression.

func Parse

func Parse(input string, isRawArg IsRawArgFunc) (Node, error)

Parse builds an AST from a rule expression. Precedence: ! > && > ||, left-associative.

type Not

type Not struct {
	X Node
}

Not is logical negation: !X.

type Or

type Or struct {
	L, R Node
}

Or is logical disjunction: L || R.

type ParseError

type ParseError struct {
	Pos int
	Msg string
}

ParseError is a lexing/parsing failure with its position.

func (*ParseError) Error

func (e *ParseError) Error() string