Clarification on value:fromBalString behaviour

[Nadeeshan96]

Description:

The spec says that

ballerina-spec/lang/lib/value.bal

Lines 111 to 113 in c88701b

	# The subset of Ballerina expression syntax supported is that produced
	# by toBalString when applied to an anydata value.
	public isolated function fromBalString(string s) returns anydata|error = external;

and #135 (comment) also says

fromBalString only works on what toBalString produces for anydata.

Does that mean we have to be restrictive and give errors for all the strings which would not be produced by value:toBalString function when value:fromBalString function is called on them?

E.g.

import ballerina/io;

public function main() {
    map<string> m = {name:"John", city:"London"};
    io:println(m.toBalString()); // {"name":"John","city":"London"}

    string str = string `{"name":"John","city":"London"}`;
    anydata|error ans = str.fromBalString(); // okay

    str = string `{"name":"John", "city":"London"}`;
    ans = str.fromBalString(); // error, because there is a space after the comma

    str = string `{name:"John",city:"London"}`;
    ans = str.fromBalString(); // error, because the keys are not quoted
}

Suggested Labels:

Code sample that shows issue:

Related Issues:

ballerina-platform/ballerina-lang#41700

[Nadeeshan96]

In the current implementation, value:fromBalString does not give an error when only whitespace characters are in between list/map elements. Since giving an error in those cases are too restrictive for the user and affect user-friendliness, the implementation is continued as it is. Hence the above snippet gives result as follows.

import ballerina/io;

public function main() {
    map<string> m = {name:"John", city:"London"};
    io:println(m.toBalString()); // {"name":"John","city":"London"}

    string str = string `{"name":"John","city":"London"}`;
    anydata|error ans = str.fromBalString(); // okay

    str = string `{"name":"John", "city":"London"}`;
    ans = str.fromBalString(); // okay

    str = string `{name:"John",city:"London"}`;
    ans = str.fromBalString(); // error, because the keys are not quoted
}

Closing the issue because further clarification is not needed.