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module lang::sexp::\syntax::SExp

rascal-0.34.0

Syntax definition for S-Expressions, based on http://people.csail.mit.edu/rivest/Sexp.txt

Usage​

import lang::sexp::\syntax::SExp;

Dependencies​

import String;
import IO;

syntax SExp​

start syntax SExp
  = string: String
  | \list: "(" SExp* ")"
  ;

syntax String​

syntax String
  = simple: SimpleString
  | display: Display SimpleString
  ;

syntax SimpleString​

syntax SimpleString
  = raw: Raw
  | token: Token
  | base64: Base64
  | hex: HexaDecimal
  | quoted: QuotedString
  ;

syntax Display​

syntax Display
  = bracket "[" SimpleString "]"
  ;

syntax Raw​

syntax Raw
  = raw: Decimal >> [:] ":" !>> [\ \t\n\r] Bytes
  ;

syntax Decimal​

lexical Decimal
  = [1-9][0-9]* !>> [0-9]
  | [0]
  ;

syntax Bytes​

lexical Bytes
  = ![]*;

syntax Token​

lexical Token
  = TokenChar+ !>> [a-zA-Z0-9\-./_:*+=]
  ;

syntax Base64​

syntax Base64
  = bracket "|" Base64Char* "|" // nb: whitespace allowed
  ;

syntax HexaDecimal​

syntax HexaDecimal
  = bracket "#" HexDigit* "#";

syntax QuotedString​

lexical QuotedString
  = [\"] QSChar* [\"] 
  ;

syntax QSChar​

lexical QSChar
  = ![\"\'\\\n\r]
  | [\\][btvnfr\"\'\\]
  | [\\][0-7][0-7][0-7]
  | [\\][x] HexDigit HexDigit
  | [\\][\n\r]
  | [\\][\r][\n]
  | [\\][\n][\r]
  ;

syntax Whitespace​

layout Whitespace
  = WS* !>> [\ \t\n\r]
  ;

syntax WS​

lexical WS
  = [\ \t\n\r]
  ;

syntax TokenChar​

lexical TokenChar
  = Alpha
  | DecimalDigit
  | SimplePunc
  ;

syntax Alpha​

lexical Alpha
  = [a-zA-Z]
  ;

syntax DecimalDigit​

lexical DecimalDigit
  = [0-9]
  ;

syntax HexDigit​

lexical HexDigit
  = [0-9A-Fa-f]
  ;

syntax SimplePunc​

lexical SimplePunc
  = [\-./_:*+=]
  ;

syntax Base64Char​

lexical Base64Char
  = Alpha
  | DecimalDigit
  | [+/=]
  ;

function raw​

Raw raw(Decimal d, Bytes bs)

function unparse​

str unparse(Bytes _)

str unparse(Decimal _)