![\"\"](\"http:\/\/blogs.kcl.ac.uk\/proged\/files\/2024\/12\/JS.png\")
<\/p>\n<\/p>\n
One lesson of programming language design? Don’t try to be too clever!<\/p>\n
Here is an example from JavaScript\u200b:<\/p>\n
When you compare<\/p>\n
0 == ‘0’<\/strong><\/p>\n the system tries to be clever: “Comparing a number and a string? You probably meant to see whether the string contains the character ‘0’, so let’s just say ‘yes’!”, it thinks. So the result is true.<\/p>\n When you compare<\/p>\n 0 == ”<\/strong><\/p>\n it tries to be even cleverer: “Ahh, perhaps you meant to check whether the length of the string is zero! Let’s just help the user here and not require them to call a ‘length’ function. So tedious. It’s true!”<\/p>\n But of course<\/p>\n ‘0’ == ”<\/strong><\/p>\n “Comparing two strings – got it. Are they the same? No! Returning false.”<\/p>\n The result of all this: The fundamental property of transitivity of equality is broken in JavaScript!<\/p>\n a == b and b == c, therefore a == c ?<\/strong><\/p>\n Not in JavaScript, it isn’t! How can anyone voluntarily program in a language like this?!<\/p>\n The lessons for me? Give me static typing any day. And don’t try to be clever when designing a language. Spelling things out is a good thing, not a bad thing.<\/p>\n","protected":false},"excerpt":{"rendered":" One lesson of programming language design? Don’t try to be too clever! Here is an example from JavaScript\u200b: When you compare 0 == ‘0’ the system tries to be clever: “Comparing a number and a string? You probably meant to … Continue reading