Category:ALGOL 68: Difference between revisions

|compat=structural

|checking=both

|LCT=yes}}

ALGOL 68 (short for ALGOrithmic Language 1968) is an [[imperative programming|imperative]] computer programming language that was conceived as a successor to the ALGOL 60 programming language, designed with the goal of a much wider scope of application and more rigorously defined syntax and semantics.

#* Loop optimization,

#* Representations - in minimal & larger character sets.

==Execute an ALGOL 68 program online==

* http://www.compileonline.com/execute_algol_online.php

==Grammar==

 

==Resources==

 

* [http://www.vim.org/scripts/script.php?script_id=1927 Vim script] providing support for syntax highlighting.

 

==Status==

*Dec. 1968: Report on the Algorithmic Language ALGOL 68 - Offprint from Numerische Mathematik, 14, 79-218 (1969); Springer-Verlag. - Edited by: A. van Wijngaarden, B.J. Mailloux, J.E.L. Peck and C.H.A. Koster.

*Sep 1973: Revised Report on the Algorithmic Language Algol 68 - Springer-Verlag 1976 - Edited by: A. van Wijngaarden, B.J. Mailloux, J.E.L. Peck, C.H.A. Koster, M. Sintzoff, C.H. Lindsey, L.G.L.T. Meertens and R.G. Fisker.

<div class="mw-collapsible-content" style="padding-left:2em;">

 

 

On some compilers, it may be necessary to include appropriate "job cards"

not too much else is required. Examples:

{|border="1" style="border-collapse: collapse; border: 5px double grey;" align="center"

FINISH

|}

At the time when ALGOL 68 was defined some predominant computers had

24 or 36 bit words, with 6 bit character sets. Hence it was desirable that

The official spec provided for different representations of the same

and Point stropping (preceeding the bold words with a dot)

A pragmatic comment may have been required to indicate which

Upper stropping (representing the bold words by upper case and

|| Algol68 as typically published

'''mode''' '''xint''' = '''int''';

'''xint''' sum sq:=0;

sum sq+:=i↑2

'''od'''

'mode' 'xint' = 'int';

'xint' sum sq:=0;

sum sq+:=i↑2

'od'

.MODE .XINT = .INT;

.XINT SUM SQ:=0;

.OD

|| RES stropping

mode .xint = int;

.xint sum sq:=0;

od

|| Upper stropping

MODE XINT = INT;

XINT sum sq:=0;

 

== Coercion (casting) ==

<div class="mw-collapsible-content" style="padding-left:2em;">

 

g

||Right hand side of:

Also:

* Units of routine-texts

* Statements yielding VOID

* All parts (but one) of a balanced clause

|bgcolor=aaaaff rowspan=4 width="50px"| deproc- eduring

|bgcolor=aaeeaa rowspan=3 width="50px"| all '''soft''' then weak deref- erencing

|colspan=1 bgcolor=ffcccc|

Widening occurs if there is no loss of precision. For example: An INT will be coerced to a REAL, and a REAL will be coerced to a LONG REAL. But not vice-versa. Examples:

INT to REAL

REAL to COMPL

BITS to []BOOL

A variable can also be coerced (rowed) to an array of length 1.

 

For example:

|-

!F<br>

m

||

*Parameters of transput calls

|colspan=3 bgcolor=ffcc99| Example:

|-

!M<br>

* Trimscripts (yielding INT)

* Enquiries: e.g. as "~" in the following

* Primaries of calls (e.g. sin in sin(x))

|colspan=4 bgcolor=ffee99|Examples:

|-

!W<br>

k

||

|colspan=5 bgcolor=aaeeaa|Examples:

REF REF INT to REF INT

REF REF REF REAL to REF REAL

|-

!S<br>

f<br>

t

|colspan=6 bgcolor=aaaaff| Example:

|}

For more details about Primaries and Secondaries refer to [[Operator_precedence#ALGOL_68|Operator precedence]].

 

== Library code used in Rosetta Code samples ==

 

{{language programming paradigm|Concurrent}}