README
¶
KVAL-Scanner
Lexical scanner for KVAL (Key Value Access Language) for KVAL-Parser
Key Value Access Language
I have created a modest specification for a key value access langauge. It allows for input and access of values to a key value store such as Golang's BoltDB.
The language specification: https://github.com/kval-access-language/KVAL
Usage
Usage is pretty low-level so will normally be done via KVAL-Parse so please see there for examples.
Scanner library is maintained in its own repo so that changes between the two can be viewed as purely as possible.
License
GPL Version 3: https://github.com/kval-access-language/KVAL-BoltDB/blob/master/LICENSE
Documentation
¶
Overview ¶
Package kvalscanner implements a basic lexical scanner for KVAL (Key Value Access Language). The language has been created for more fluid access to Key-Value-like databases such as the popular BoltDb.
Parsers can access a new Scanner() to check that a user provided string is valid according to the language's specification. For Golang, however, this work is already done for you at http://github.com/wayblink/kval-parse
The most up-to-date specification for KVAL can be found here: https://github.com/wayblink/kval
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ErrorLookup = map[Token]string{ ILLEGAL: "ILLEGAL", EOF: "EOF", WS: "WHITESPACE", LITERAL: "LITERAL", BUCKEY: "BUCKET >>>> KEY", BUCBUC: "BUCKET >> BUCKET", KEYVAL: "KEY :: VALUE", ASSIGN: "ASSIGNMENT", USCORE: "UNDERSCORE", OPATT: "OPEN REGEX PATTERN", CPATT: "CLOSE REGEX PATTERN", INS: "INSERT KEYWORD", GET: "GET KEYWORD", LIS: "LIS KEYWORD", DEL: "DEL KEYWORD", REN: "REN KEYWORD", REGEX: "REGEX PATTERN", }
ErrorLookup map is used to look up an error and provide a human readable response
var KeywordMap = map[string]int{
"INS": 0x1,
"ins": 0x1,
"Ins": 0x1,
"GET": 0x2,
"get": 0x2,
"Get": 0x2,
"LIS": 0x3,
"lis": 0x3,
"Lis": 0x3,
"DEL": 0x4,
"del": 0x4,
"Del": 0x4,
"REN": 0x5,
"ren": 0x5,
"Ren": 0x5,
}
KeywordMap values exported for KVAL Parser to verify keywords Lookup 'LIT' value in KeyWordMap and if found we have a KVAL key word, e.g. INS, GET, LIS, REN, DEL. If used correctly this map will help a parser take care of and case-sensitivity issues when users specify query strings.
Functions ¶
This section is empty.
Types ¶
type Scanner ¶
type Scanner struct {
// contains filtered or unexported fields
}
Scanner represents a lexical scanner.
func NewScanner ¶
NewScanner returns a new instance of Scanner.
type Token ¶
type Token int
Token represents a lexical token.
const ( ILLEGAL Token = iota // Spacial token, ILLEGAL: Token is an illegal character EOF // Spacial token, EOF: Token signals the end of input WS // Spacial token, WS: Token signals whitespace has been found LITERAL // LITERAL: String literal discovered BUCKEY // Other operator, BUCKKEY: >>>> Bucket to Key syntax for KVAL BUCBUC // Other operator, BUCBUC: >> Bucket to Bucket syntax for KVAL KEYVAL // Other operator, KEYVALL :: Key to Value syntax for KVAL ASSIGN // Other operator, ASSIGN: => Assignment operator for KVAL renames USCORE // Single character operator, USCORE: _ Return unknown Key or Value OPATT // Single character operator, OPATT: { Open a regular expression pattern CPATT // Single character operator, COATT: } Close a regular expression pattern INS // Keyword, INS: Insert capability of KVAL GET // Keyword, GET: Get capability of KVAL LIS // Keyword, LIS: LIS capability of KVAL DEL // Keyword, DEL: Delete capability of KVAL REN // Keyword, REN: Rename capability of KVAL REGEX // Regular expression, REGEX: {PATT} ANy regex pattern inside OPATT and CPATT )
Tokens to scan for that satisfy the KVAL (Key Value Access Language) specification
Source Files