Editing Off-side rule (section)

==Alternatives==
The primary alternative to delimiting blocks by indenting, popularized by broad use and influence of the language [[C (programming language)|C]], is to ignore [[whitespace character]]s and mark blocks explicitly with [[curly bracket]]s (i.e., <code>{</code> and <code>}</code>) or some other delimiter. While this allows for more formatting freedom – a developer might choose not to indent small pieces of code like the [[Control flow#Continuation with next iteration|break and continue statements]] – sloppily indented code might lead the reader astray, such as the [[goto fail]] bug.

[[Lisp (programming language)|Lisp]] and other [[S-expression]]-based languages do not differentiate statements from expressions, and parentheses are enough to control the scoping of all statements within the language. As in curly bracket languages, whitespace is mostly ignored by the reader (i.e., the read function). Whitespace is used to separate tokens.<ref>{{Cite web|url=http://clhs.lisp.se/Body/02_adg.htm|title = CLHS: Section 2.1.4.7}}</ref> The explicit structure of Lisp code allows automatic indenting, to form a visual cue for human readers.

Another alternative is for each block to begin and end with explicit keywords. For example, in [[ALGOL 60]] and its descendant [[Pascal (programming language)|Pascal]], blocks start with [[Reserved word|keyword]] <code>begin</code> and end with keyword <code>end</code>. In some languages (but not Pascal), this means that newlines ''are'' important{{citation needed|date=June 2012}} (unlike in curly brace languages), but the indentation is not. In [[BASIC]] and [[Fortran]], blocks begin with the block name (such as <code>IF</code>) and end with the block name prepended with <code>END</code> (e.g., <code>END IF</code>). In [[Fortran]], each and every block can also have its own unique block name, which adds another level of explicitness to lengthy code. [[ALGOL 68]] and the [[Bourne shell]] (sh, and [[Bash (Unix shell)|bash]]) are similar, but the end of the block is usually given by the name of the block written backward (e.g., <code>case</code> starts a [[switch statement]] and it spans until the matching <code>esac</code>; similarly [[conditional (computer programming)|conditionals]] <code>if</code>...<code>then</code>...[<code>elif</code>...[<code>else</code>...]]<code>fi</code> or [[for loop|''for'' loops]] <code>for</code>...<code>do</code>...<code>od</code> in ALGOL68 or <code>for</code>...<code>do</code>...<code>done</code> in bash).

An interesting variant of this occurs in [[Modula-2]], a Pascal-like language which does away with the difference between one and multiline blocks. This allows the block opener (<code>{</code> or <code>BEGIN</code>) to be skipped for all but the function level block, requiring only a block terminating token (<code>}</code> or <code>END</code>). It also fixes [[dangling else]]. Custom is for the <code>end</code> token to be placed on the same indent level as the rest of the block, giving a blockstructure that is very readable.

One advantage to the [[Fortran]] approach is that it improves readability of long, nested, or otherwise complex code. A group of outdents or closing brackets alone provides no contextual cues as to which blocks are being closed, necessitating backtracking, and closer scrutiny while [[debugging]]. Further, languages that allow a suffix for END-like keywords further improve such cues, such as <code>continue</code> versus <code>continue for x</code>, and [[For loop#1964: BASIC | end-loop marker specifying the index variable]] <code>NEXT I</code> versus <code>NEXT</code>, and [[For loop#Early exit and continuation | uniquely named loops]] <code>CYCLE X1</code> versus <code>CYCLE</code>. However, modern [[source code editor]]s often provide visual indicators, such as [[syntax highlighting]], and features such as [[code folding]] to assist with these drawbacks.