I am very beginner to PEGjs I need help to implement variable (identifier) declaration support to my parser.
My input code look like:
a=4;
print a
My PEGjs grammer:
start
=(line)*
line
=left:var"="right:integer";" {left=right;}
/
print middle:var {return middle;}
print
="print"
var
=(a-zA-z)+
Integer "integer"
= _ [0-9]+ { return parseInt(text(), 10); }
Expected output: 4
Please help me. #ThanksInAdvance
try this:
all
= _ mn:multiPutN _ pn:printN _
{
return mn[pn];
}
multiPutN
= mp:putN+ _
{
var r = {};
mp.forEach(it => {
r[it[0]]=it[1];
});
return r;
}
putN
= vn:varName _ "=" _ nn:n _ ";" { return [vn, nn]}
printN
= print _ n:varName _ {return n;}
varName
= [a-zA-Z]+ {return text();}
print
="print"
n "integer number"
= _ [0-9]+ { return parseInt(text(), 10); }
_ "whitespace or new line"
= [ \t\n\r]*
so that code above also support multi variables but can only print one variable. I wrote the grammar based in your example so when assigning variable value you need to put ";" at the end but print var should not need with that