Editing ALGOL 68 (section)

===Units: Expressions===
The basic language construct is the ''unit''. A unit may be a ''formula'', an ''enclosed clause'', a ''routine text'' or one of several technically needed constructs (assignation, jump, skip, nihil). The technical term ''enclosed clause'' unifies some of the inherently bracketing constructs known as ''block'', ''do statement'', ''switch statement'' in other contemporary languages. When keywords are used, generally the reversed character sequence of the introducing keyword is used for terminating the enclosure, e.g. ( '''IF''' ~ '''THEN''' ~ '''ELSE''' ~ '''FI''', '''CASE''' ~ '''IN''' ~ '''OUT''' ~ '''ESAC''', '''FOR''' ~ '''WHILE''' ~ '''DO''' ~ '''OD''' ). This [[Guarded Command Language#Selection: if|Guarded Command]] syntax was reused by [[Stephen R. Bourne|Stephen Bourne]] in the common [[Unix]] [[Bourne shell]]. An expression may also yield a ''multiple value'', which is constructed from other values by a ''collateral clause''. This construct just looks like the parameter pack of a procedure call.