Request ljs2lua

[bferguson3]

I'd like to be able to code using ljs and then run it in an interpreted environment that uses standard lua 5.1 code (eg love2d/lovr).

Can you make a reverse converter?

[mingodad]

Probably yes but I do not need it, could you do it too and share it ?

[Shadowblitz16]

I would like this too for love2d

[Artoria2e5]

It would really help to have a grammar instead of following the C parser. I know it's a simple recursive-descent, but code is always more complicated to the eye than what's in lua-parser.ly.

Having more parsers also opens up the opportunity to get code formatters. A port of prettier-lua to ljs would... fix some complaints about how many people prefers to have a space after flow-control keywords and no space before the : in typing.

[mingodad]

Thank you for your interest and feedback !
Here you have an EBNF grammar compatible with https://www.bottlecaps.de/rr/ui for railroad diagram generation (I need to add it to the repository eventually). Copy the grammar bellow and paste on the Edit Grammar tab then switch to the View Diagram tab on https://www.bottlecaps.de/rr/ui (any feedback is welcome).

//"--" lf cr  '+' lf  '+' tab
Ljs ::= statlist
statlist ::=  ( statement  )*
statement ::= ';'  | ifstat  | whilestat  | block  | forstat  | dowhilestat  | funcstat  |  ( "local"  | "var"  | "let"  | "auto"  )  ( "function" localfunc  | localstat  )  | labelstat  | "return" retstat  | gotostat  | exprstat
ifstat ::= "if" test_then_block  ( "else" statement  )?
test_then_block ::= '(' expr ')' statement
block ::= '{' statlist '}'
whilestat ::= "while" '(' cond ')' statement
forstat ::= "for" '(' TK_NAME  ( fornum  | forlist  )
fornum ::= '=' expr ',' expr  ( ',' expr  )? forbody
forlist ::=  ( ',' TK_NAME  )* TK_IN explist forbody
forbody ::= ')' statement
dowhilestat ::= "do" '{' statlist '}' "while" '(' cond ')'
cond ::= expr
funcstat ::= "function" funcname body
funcname ::= singlevar  ( '.' fieldsel  )*  ( "::" fieldsel  )?
singlevar ::= str_checkname
body ::= '('  ( parlist  )? ')'  ( ':' TK_NAME  )? '{' statlist '}'
parlist ::= TK_DOTS  ( ':' TK_NAME  )?  | TK_NAME  ( ':' TK_NAME  )?  ( ','  ( TK_NAME  | TK_DOTS  )  ( ':' TK_NAME  )?  )*
localfunc ::= TK_NAME body
localstat ::= name_attribute  ( ',' name_attribute  )*  ( '=' explist  )?
name_attribute ::= TK_NAME  ( getlocalattribute  )?  ( ':' TK_NAME  )?
getlocalattribute ::= '<'  ( "const"  | "close"  ) '>'
labelstat ::= TK_NAME ':'
retstat ::=  ( explist  )?  ( ';'  )?
gotostat ::= "goto" str_checkname  | "break"  | "continue"
inc_dec_op ::=  ( "++"  | "--"  )
exprstat ::= suffixedexp  ( assign_compound  | assignment  | ';'  )?
assignment ::= ','  | '='
assign_compound ::= TK_CADD  | TK_CSUB  | TK_CMUL  | TK_CDIV  | TK_CMOD
suffixedexp ::= primaryexp  ( '.' fieldsel  | '[' yindex  | "->" checkname funcargs  | funcargs  | inc_dec_op  )*
primaryexp ::= '(' expr ')'  | singlevar  | inc_dec_op
fieldsel ::= checkname
checkname ::= codestring
codestring ::= str_checkname
str_checkname ::= TK_NAME
yindex ::= expr ']'
funcargs ::= '('  ( explist  )? ')'
tconstructor ::=  ( field  (  ( ','  | ';'  ) field  )*  )? '}'
field ::= TK_NAME recfield  | '[' yindex recfield  | listfield
listfield ::= expr
recfield ::= '=' expr
explist ::= expr  ( ',' expr  )*
expr ::= subexpr  ( '?' expr ':' expr  )?
subexpr ::=  (  ( getunopr subexpr  )  | simpleexp  )  ( getbinopr subexpr  )*
getunopr ::= "not"  | '-'  | '~'  | '#'
getbinopr ::= '+'  | '-'  | '*'  | '%'  | '^'  | '/'  | "idiv"  | '&'  | '|'  | '!'  | "<<"  | ">>"  | ".."  | "!="  | "=="  | '<'  | "<="  | '>'  | ">="  | "&&"  | "||"
simpleexp ::= TK_FLT  | TK_INT  | TK_STRING  | TK_NIL  | TK_TRUE  | TK_FALSE  | TK_DOTS  | '{' tconstructor  | TK_FUNCTION body  | suffixedexp

letter ::= "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_"
oct ::= '0'  .. '7'
digit ::= '0'  .. '9'
nzdigit ::= '1'  .. '9'
cr ::= '\r'
lf ::= '\n'
tab ::= '\t'
stringCh ::= ANY  '-' '"'  '-' '\'  '-' cr  '-' lf
charCh ::= ANY  '-' "'"  '-' '\'  '-' cr  '-' lf
longStringCh ::= ANY  '-' "]]"
printable ::= '\u0020'  .. '\u007e'
hex ::= digit  '+' 'a'  .. 'f'  '+' 'A'  .. 'F'
TK_NAME  ::= letter  ( letter  | digit  )*
TK_FLT  ::=  ( '.' digit  ( digit  )*  (  ( 'e'  | 'E'  )  ( '+'  | '-'  )? digit  ( digit  )*  )?  | digit  ( digit  )* '.'  ( digit  )*  (  ( 'e'  | 'E'  )  ( '+'  | '-'  )? digit  ( digit  )*  )?  | digit  ( digit  )*  ( 'e'  | 'E'  )  ( '+'  | '-'  )? digit  ( digit  )*  )
TK_INT  ::=  ( digit  ( digit  )*  |  ( "0x"  | "0X"  ) hex  ( hex  )*  )
TK_STRING  ::= '"'  ( stringCh  | '\'  ( printable  |  ( '\r'  )? '\n'  )  )* '"'  | "'"  ( charCh  | '\'  ( printable  |  ( '\r'  )? '\n'  )  )* "'"  | "[["  ( longStringCh  )* "]]"
badString  ::= '"'  ( stringCh  | '\' printable  )*  ( cr  | lf  )  | "'"  ( charCh  | '\' printable  )*  ( cr  | lf  )
TK_AUTO  ::= "auto"
TK_BREAK  ::= "break"
TK_CONTINUE  ::= "continue"
TK_DO  ::= "do"
TK_ELSE  ::= "else"
TK_FALSE  ::= "false"
TK___FILE__  ::= "__FILE__"
TK_FOR  ::= "for"
TK_FUNCTION  ::= "function"
TK_GOTO  ::= "goto"
TK_IDIV  ::= "idiv"
TK_IF  ::= "if"
TK_IN  ::= "in"
TK_LET  ::= "let"
TK___LINE__  ::= "__LINE__"
TK_LOCAL  ::= "local"
TK_NIL  ::= "null"
TK_RETURN  ::= "return"
TK_TRUE  ::= "true"
TK_VAR  ::= "var"
TK_WHILE  ::= "while"
TK_AND  ::= "&&"
TK_NOT  ::= '!'
TK_OR  ::= "||"
TK_POW  ::= "**"
TK_CONCAT  ::= ".."
TK_DOTS  ::= "..."
TK_EQ  ::= '='
TK_GE  ::= ">="
TK_LE  ::= '<'
TK_NE  ::= "!="
TK_CADD  ::= "+="
TK_CSUB  ::= "-="
TK_CMUL  ::= "*="
TK_CDIV  ::= "/="
TK_CMOD  ::= "%="
TK_CCONCAT  ::= "..="
TK_PLUSPLUS  ::= "++"
TK_MINUSMINUS  ::= "--"
TK_SHL  ::= "<<"
TK_SHR  ::= ">>"
TK_ARROW  ::= "->"
TK_DBCOLON  ::= "::"