|
==Type systems==
{{main|Comparison of programming languages by type system}}
==Failsafe I/O and system calls==
Most programming languages will print an [[error message]] or throw an [[exception handling|exception]] if an [[input/output]] operation or other [[system call]] (e.g., [[chmod]], [[kill (Unix)|kill]]) fails, unless the programmer has explicitly arranged for different handling of these events. Thus, these languages [[failsafe|fail safely]] in this regard.
Some (mostly older) languages require that programmers explicitly add checks for these kinds of errors. Psychologically, different [[List of cognitive biases|cognitive biases]] (e.g., [[optimism bias]]) may affect novices and experts alike and lead them to skip these checks. This can lead to [[software bug|erroneous behavior]].
'''Failsafe I/O''' is a feature of [[1C:Enterprise programming language|1C:Enterprise]], [[Ada (programming language)|Ada]] (exceptions), [[ALGOL]] (exceptions or return value depending on function), [[Ballerina (programming language)|Ballerina]], [[C Sharp (programming language)|C#]], [[Common Lisp]] ("conditions and restarts" system), [[Curry (programming language)|Curry]], [[D (programming language)|D]] (throwing on failure),<ref>{{Cite web|url=https://dlang.org/phobos/std_stdio.html|title=STD.stdio - D Programming Language}}</ref> [[Erlang (programming language)|Erlang]], [[Fortran]], [[Go (programming language)|Go]] (unless result explicitly ignored), [[Gosu (programming language)|Gosu]], [[Harbour (programming language)|Harbour]], [[Haskell]], [[ISLISP]], [[Java (programming language)|Java]], [[Julia (programming language)|Julia]], [[Kotlin (programming language)|Kotlin]], [[LabVIEW]], [[Mathematica]], [[Objective-C]] (exceptions), [[OCaml]] (exceptions), [[OpenLisp]], [[PHP]], [[Python (programming language)|Python]], [[Raku (programming language)|Raku]], [[Rebol]], [[Rexx]] (with optional '''signal on'''... trap handling), [[Ring (programming language)|Ring]], [[Ruby (programming language)|Ruby]], [[Rust (programming language)|Rust]] (unless result explicitly ignored), [[Scala (programming language)|Scala]],<ref>Scala runs on the Java Virtual Machine from which it inherits the runtime exception handling.</ref> [[Smalltalk]], [[Standard ML]] {{citation needed|date=February 2011}}, [[Swift (programming language)|Swift ≥ 2.0]] (exceptions), [[Tcl]], [[Visual Basic (classic)|Visual Basic]], [[Visual Basic (.NET)|Visual Basic .NET]], [[Visual Prolog]], [[Wolfram Language]], [[Xojo]], [[XPath]]/[[XQuery]] (exceptions), and [[Zeek]].
'''No Failsafe I/O''':
[[AutoHotkey]] (global ErrorLevel must be explicitly checked), [[C (programming language)|C]],<ref name="VS">[[GNU compiler collection|gcc]] can warn on unchecked [[errno.h|errno]]. Newer versions of [[Visual Studio]] usually throw exceptions on failed I/O when using [[C file input/output|stdio]].</ref> [[COBOL]], [[Eiffel (programming language)|Eiffel]] (it actually depends on the library and it is not defined by the language), [[GLBasic]] (will generally cause program to crash), [[IBM RPG|RPG]], [[Lua (programming language)|Lua]] (some functions do not warn or throw exceptions), and [[Perl]].<ref>Considerable error checking can be enabled optionally, but by default Perl is not failsafe.</ref>
Some I/O checking is built in [[C++]] ([[Input/output (C++)|STL iostreams]] throw on failure but C APIs like [[C file input/output|stdio]] or [[C POSIX library|POSIX]] do not)<ref name="VS"/> and [[Object Pascal]], in [[Bash (Unix shell)|Bash]]<ref><code>set -e</code> enables termination if any unchecked [[exit status]] is nonzero.</ref> it is optional.
==Expressiveness==
|
