4 ms·

This is me being obtuse, but it seems like an appropriate time to ask... What is the difference? You mention that each value has one known type in a strongly ty

by asxd 5y ago

This is me being obtuse, but it seems like an appropriate time to ask... What is the difference? You mention that each value has one known type in a strongly typed language. Isn't this the case for Javascript as well? I'm having a difficult time trying to conjure a situation in JS where a value has multiple types (but I'm certainly no expert in JS).

DemocracyFTW 5y ago
It's a bit of a mixed bag and the terminology is difficult to grasp. I'd say Tcl and Bash are languages that only have strings ('stringly typed') that can be interpreted in a number of ways. JavaScript, PHP, and SQLite's SQL OTOH have lots of implicit type coercion---`1` and `'1'` can both act as a string, a number, or a boolean. Python is considerably more picky in what it allows in which constructs; it does all the numerical typing stuff implicitly (so switching between integer, big int, and float happens most of the time without users even knowing about it), and b/c of backwards compatibility, coercions between numbers and booleans still happen (`True + 1` is still `2` in Python3.9). By extension, this includes empty lists, strings, and dictionaries evaluating to `False` in appropriate contexts. I believe that in retrospect most of these efforts—coming up with a Just Works arrangement of strategically placed implicit coercions—that so much defined the rise of scripting languages in the 90s are questionable. Subsequently, many millions of USD went into making JavaScript faster than reasonable (on V8) giving its pervasive dynamic nature. Just bolting down types and banning any implicit coercions would have given it similar performance gains with a fraction of effort and a fraction of the resulting complexity. Backward compatibility could have been done with a pragma similar to the existing `'use strict'`. I guess what I want to say is that strong and loose typing exists on a continuum much like human languages are never just of a single idealized kind.
deleted 5y ago
[deleted]
L0stLink 5y ago
JavaScript will dynamically change the effective type of a value like sting or number into another depending on the operation being performed on it: '2' * 3 => 6 '2' + 3 => '23'

by asxd 5y ago

DemocracyFTW 5y ago

It's a bit of a mixed bag and the terminology is difficult to grasp. I'd say Tcl and Bash are languages that only have strings ('stringly typed') that can be interpreted in a number of ways. JavaScript, PHP, and SQLite's SQL OTOH have lots of implicit type coercion---`1` and `'1'` can both act as a string, a number, or a boolean. Python is considerably more picky in what it allows in which constructs; it does all the numerical typing stuff implicitly (so switching between integer, big int, and float happens most of the time without users even knowing about it), and b/c of backwards compatibility, coercions between numbers and booleans still happen (`True + 1` is still `2` in Python3.9). By extension, this includes empty lists, strings, and dictionaries evaluating to `False` in appropriate contexts. I believe that in retrospect most of these efforts—coming up with a Just Works arrangement of strategically placed implicit coercions—that so much defined the rise of scripting languages in the 90s are questionable. Subsequently, many millions of USD went into making JavaScript faster than reasonable (on V8) giving its pervasive dynamic nature. Just bolting down types and banning any implicit coercions would have given it similar performance gains with a fraction of effort and a fraction of the resulting complexity. Backward compatibility could have been done with a pragma similar to the existing `'use strict'`. I guess what I want to say is that strong and loose typing exists on a continuum much like human languages are never just of a single idealized kind.

deleted 5y ago

[deleted]

L0stLink 5y ago

JavaScript will dynamically change the effective type of a value like sting or number into another depending on the operation being performed on it: '2' * 3 => 6 '2' + 3 => '23'