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pretty-print a map?

adamohernadamohern Member, OS Professional Posts: 216 PRO

The above is really hard on the eyes. I find it difficult to read. Is there a way to print out nested maps and arrays with better formatting?


  • Options
    kevin_o_toole_1kevin_o_toole_1 Onshape Employees, Developers, HDM Posts: 565
    In FeatureScript, it's beneficial to define types for the data you're using. This lets you write functions that accept only that type, and overload functions for that type — including toString().

    So something like:
    // new type
    export type MyType typecheck isMyType;
    export predicate isMyType(value)
        value is map;
    // constructor
    export function myType(id is number, length is ValueWithUnits, endPoint is Vector,
        axialRotation is ValueWithUnits, orientation is Vector) returns MyType
        return {"id" : id, "length" : length, "endPoint" : endPoint,
            "axialRotation" : axialRotation, "orientation" : orientation } as MyType;
    // overloads
    export function toString(value is MyType) returns string
        var out is string = "MyType:";
        for (var entry in value)
            out ~= "\n" ~ entry.key ~ ": ";
            out ~= toString(entry.value);        
        return out;
    export function debug(value is MyType)
        // call debug() on the relevant data in this type

    I'm not sure about your exact use case, but for sake of conciseness in the type, it might be nicer to group endPoint, axialRotation, and orientation into a single CoordSystem to start with (personally, I find it mind-numbing trying to do vector math unless I'm starting with a CoordSystem and can call fromWorld() everywhere).

    In the future, we'd like to have a nicer way of presenting big chunks of native data by default (even when custom types aren't defined), but today, untyped data is printed as a big long literal.
  • Options
    kevin_o_toole_1kevin_o_toole_1 Onshape Employees, Developers, HDM Posts: 565
    Update: I misinterpreted the state of std. Turns out, we do have a decent toString() method defined on maps. The trick is to actually call toString, before string concatenation.
    println("my map is " ~ toString(myMap));
    // or simply
    Making a type is still good practice, but for the pretty-printing, calling the preexisting toString() will be much better than what you're seeing above.

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