Format Checker

Programs are meant to be read by humans and only incidentally for computers to execute.

— H. Abelson and G. Sussman
Structure and Interpretation of Computer Programs

Background 

Most programming languages promote a uniform style for formatting code, either with style guide documents (e.g. Python’s PEP 8) or utilities (aka “linters”).

THT goes a step further. It has a Format Checker that identifies issues at compile time.

The format rules were collected from the most commonly used style guides for comparable languages (typically Java & JavaScript).

Benefits

• Clean, consistent code is easier to read & understand.
• Clean code is more enjoyable to work with.
• Clean code is less prone to bugs.
• Sharing code online is easier.
• Novices will learn best practices quicker.
• Teams will spend less time debating what rules to follow.
• No extra steps in the build process to setup and configure.

Using conventions frees your brain from the mundane aspects of programming, which offer little payback.

— Steve McConnell, Code Complete

Formatting Rules 

General

• No lines over 100 characters long. Exceptions are multi-line strings and template functions.
• UNIX newlines. Line endings should be set to LF (UNIX). Not CRLF (Windows).
• UTF-8. Files should be saved as UTF-8 encoded.

Tab Characters

TAB characters are interpreted by THT to be 4 spaces.

However, we recommend you configure your editor to insert 4 spaces for your Tab key (aka “soft tabs”), if it doesn’t already do so by default.

• Notepad++
• SublimeText

Whitespace

Indentation

Lines inside multiline braces of {}, [], or () should be indented. Recommended: 4 spaces

// ✖ No
$nums = [
'Do',
'Re',
'Mi'
];

// ✔ Yes
$nums = [
    'Do',
    'Re',
    'Mi'
];

Infix operators + = == &&

Space before & after: YES

$a = $b + 1;  // ✔ Yes
$a = $b+1;    // ✖ No
$a=$b+1;      // ✖ No

if $isGood && $isOk { ... }  // ✔ Yes
if $isGood&&$isOk { ... }    // ✖ No

Prefix operators ! -

Spaces after: NO

$isNormal = !$isAdmin;   // ✔ Yes
$isNormal = ! $isAdmin;  // ✖ No

if !$isAdmin { ... }    // ✔ Yes
if ! $isAdmin { ... }   // ✖ No

$a = -23;   // ✔ Yes
$a = - 23;  // ✖ No

Semicolons ;

Space before: NO
Limit: Only one statement per line.

$foo = 1;   // ✔ Yes
$foo = 1 ;  // ✖ No

$foo = 1; $bar = 2;  // ✖ No

Commas ,

Space before: NO
Space after: YES

doSomething($a, $b, $c);  // ✔ Yes
doSomething($a,$b,$c);    // ✖ No

Parentheses ( )

Inside padding: NO

doSomething($myVar);    // ✔ Yes
doSomething( $myVar );  // ✖ No

$a = $b / ($c / $d);    // ✔ Yes
$a = $b / ( $c / $d );  // ✖ No

Square braces [ ]

Inside padding: NO

$a = [1, 2, 3];    // ✔ Yes
$a = [ 1, 2, 3 ];  // ✖ No

$user['userId'];    // ✔ Yes
$user[ 'userId' ];  // ✖ No

Curly braces { }

Inside padding: YES

$a = { foo: 1 };  // ✔ Yes
$a = {foo: 1};    // ✖ No

if $isOk { return $a; }  // ✔ Yes
if $isOk {return $a;}    // ✖ No

Colons :

Space before: NO
Space after: YES

$a = { foo: 1 };   // ✔ Yes

$a = { foo : 1 };  // ✖ No
$a = { foo:1 };    // ✖ No

Function argument list ( )

Space before: NO
Space after: YES

F foo($myVar) {   // ✔ Yes

F foo($myVar){    // ✖ No
F foo ($myVar)    // ✖ No

Open braces {

Space before: YES
Same line: YES
Next line: NO (but allowed)

// ✔ Yes
F main() {
    // ...
}

// ✖ No - no space before {
F main(){
    // ...
}

// ✖ No - but allowed
F main()
{
    // ...
}

Closing braces } ]

Next Line: YES

// ✔ Yes
$nums = [
    111,
    222,
];

// ✖ No
$nums = [
    111,
    222 ];

Parser Rules 

Assignment inside conditional: NO

// ✖ No
if $line = readLine() { ... }

// ✔ Yes
$line = $readLine();
if $line { ... }

Nested ternary expressions: NO

// ✖ No
$a = check1 ? action1() : check2 ? action2() : action3();

// ✔ Yes - if/else
$a = '';
if check1 {
    $a = action1();
} else if check2 {
    $a = $action2();
} else {
    $a = $action3();
}

// ✔ Yes - match with one-liner syntax
$a = '';
match {
    check1:   $a = action1();
    check2:   $a = action2();
    default:  $a = action3();
}

Names

Module and class names are strict UpperCamelCase. This includes acronyms.

User
XmlReader
XmlHttpRequest

All other names (variables, functions, bare map keys) are strict camelCase. This includes acronyms.

user
firstName
userId
userHasIphone
httpResponse

HTML Templates 

These are additional rules for markup within HTML Template Functions.

Tag Names

Uppercase: NO

// ✖ No
<SPAN>

// ✔ Yes
<span>

Parameters

Quoted: YES

// ✖ No
<div class=my-class>

// ✔ Yes
<div class="my-class">

Space around equals: NO

// ✖ No
<div class = "my-class">

// ✔ Yes
<div class="my-class">