Some programming languages allow conditional value assignments that look like
x = (IF condition THEN a ELSE b)
My search-fu is failing me: how do we call such statements in the jargon of programming languages?
It evokes functional programming, though some imperative languages achieve the same with a "ternary operator". In order to find relevant documentation for my favorite languages, I would really love to know the proper vocabulary!
Thanks a lot
My search-fu is failing me: how do we call such statements in the jargon of programming languages?
We don't. It's an expression, not a statement. If it were a statement, it wouldn't have a value. (Unless by "such statements" you are referring to the assignment?)
In order to find relevant documentation for my favorite languages, I would really love to know the proper vocabulary!
You will have to look at the documentation for your favorite languages, then. Different language communities come up with different terms for pretty much everything. (E.g. "member function" in C++, "method" in Java, and "routine" in Eiffel are all the same thing whereas "method" in Java and "method" in CLU are different things, and "function" in C and "function" in Pascal are different things.)
In Ruby, the general construct is called a conditional expression (see section 11.5.2.2 Conditional expressions of the ISO/IEC 30170:2012 Information technology — Programming languages — Ruby specification). There are four different kinds of conditional expressions:
The if expression (sec. 11.5.2.2.2):
if cond1 then e1 elsif cond2 then e2 elsif cond3 then e3 else e4 end
Note: the then keyword can also be replaced with an expression separator (semicolon or linebreak).
The unless expression (sec. 11.5.2.2.3):
unless cond1 then e1 else e2 end
Note: the then keyword can also be replaced with an expression separator (semicolon or linebreak).
The case expression (sec. 11.5.2.2.4). There are three forms of the case expression:
conditional (official name: case expression without expression):
case when cond1 then e1 when cond2 then e2 when cond3 then e3 else e4 end
matching (official name: case expression with expression):
case scrutinee when match1 then e1 when match2 then e2 when match3 then e3 else e4 end
case scrutinee in pat1 => capture1 if cond1 then e1 in pat2 => capture2 unless cond2 then e2 in pat3 => capture3 if cond3 then e3 else e4 end
Note that pattern matching is not covered by the ISO Ruby Language Specification, since it was added later.
Note: the then keyword can also be replaced with an expression separator (semicolon or linebreak).
The conditional operator expression (sec. 11.5.2.2.5):
cond ? e1 : e2
In ECMAScript, it is called the conditional operator (see section 12.14 Conditional Operator ( ? : ) of the ECMAScript Specification):
cond ? e1 : e2
In Python, it is called the conditional expression (see section 6.13 Conditional expressions of the Python Language Reference and PEP 308 – Conditional Expressions):
e1 if cond else e2
In Scala, it is called the conditional expression (see section 6.16 Conditional Expressions of the Scala Language Specification):
if (cond) e1 else e2
or with the New Control Syntax in Scala 3:
if cond then e1 else e2
In Java, it is called the conditional operator (see section 15.25 Conditional Operator ? : of the Java Language Specification):
cond ? e1 : e2
although technically, a switch expression (see section 15.28 switch expressions of the Java Language Specification) would also fit the bill:
switch (selector) { case cond1 -> e1; case cond2 -> e2; default -> e3; }
In C#, it is called the conditional operator:
cond ? e1 : e2
However, some of the pattern matching features in current versions of C# would also fit the bill.
I'm a full-time functional programmer, and have usually heard it called simply "an if expression," as opposed to an if statement. Expressions return values whereas statements are executed for their side effects.
Unfortunately, imperative programmers often use "expression" and "statement" almost interchangeably, so it's probably not a universally recognized term.
