I want to replace variables in an input with it's value from javascript variables. It's possible that the variable name is a path of an object with functions in the middle or at the end: object.property.someFunction().propertyOfFunctionResult
.
The grammar for this looks like:
funParameter: '(' value? (', ' value)* ')' ;
value: INT | BOOL | STRING | variable;
varname: VAR ;
variable: (varname | '{' value '}') funParameter? ('.' variable)* ;
The visitor-function for variable
(everything involving customValue
is just how I would imagine how to do it):
visitVariable(ctx) {
var key, val;
if(ctx.value()) {
key = this.visit(ctx.value());
} else if(ctx.varname()) {
key = ctx.varname().getText();
}
if(ctx.funParameter()) {
//idea:
val = this.callFunction(key, this.visit(ctx.funParameter()), ctx.customValue); //pass value to function call
} else {
//idea:
if(ctx.customValue) {
val = ctx.customValue[key]; //Get value from parent
} else {
val = this.vars[key]; //Get value from JS-variables
}
}
if(ctx.variable()) {
//idea:
val = this.visit(ctx.variable(), {customValue:val});
}
return val;
}
The problem is, that I don't know how to pass the current value of the JS-variable down the parse tree. When object
is evaluated I would need to pass the JS-object in the visitor down so that in the next visitVariable
it's clear that I want to return the value of object.property
. Any hints are appreciated.
It's probably kind of hacked, but the function getParent()
, that is described in the docs, was not available in the ctx
-object. But I found ctx.parentCtx
. Now I'm just assigning ctx.customValue = 'somevalue'
and can access it from the children with ctx.parentCtx.customValue
.
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