ECL (data-centric programming language): Difference between revisions

Revision as of 14:26, 4 December 2019

Latest revision as of 03:56, 18 July 2025

(8 intermediate revisions by 8 users not shown)

Line 1:

{{Short description|None}}

{{Infobox programming language

| name = ECL

Line 12 ⟶ 13:

| influenced_by = [[Prolog]], [[Pascal (programming language)|Pascal]], [[SQL]], [[Snobol4]], [[C++]], [[Clarion (programming language)|Clarion]]

| influenced =

| operating_system = [[GNU]]/[[Linux kernel|Linux]]

| license =

| website = http://hpccsystems.com/

}}

'''ECL''' (Enterprise Control Language) is a declarative, data -centric programming language designed in 2000 to allow a team of programmers to process [[big data]] across a high performance computing cluster without the programmer being involved in many of the lower level, imperative decisions.<ref>[http://www.lexisnexis.com/risk/about/guides/program-guide.html A Guide to ECL], [[Lexis-Nexis]].]</ref><ref>"Evaluating use of data flow systems for large graph analysis," by A. Yoo, and I. Kaplan. Proceedings of the 2nd Workshop on Many-Task Computing on Grids and Supercomputers, MTAGS, 2009</ref>

== History ==

Line 23 ⟶ 24:

== Language constructs ==

ECL, at least in its purest form, is a declarative, data -centric language. Programs, in the strictest sense, do not exist. Rather an ECL application will specify a number of core datasets (or data values) and then the operations which are to be performed on those values.

=== Hello world ===

Line 30 ⟶ 31:

Perhaps a more flavorful example would take a list of strings, sort them into order, and then return that as a result instead.

<sourcesyntaxhighlight lang="ecl">

// First declare a dataset with one column containing a list of strings

// Datasets can also be binary, CSV, XML or externally defined structures

Line 37 ⟶ 38:

SD := SORT(D,Value);

output(SD)

</syntaxhighlight>

</source>

The statements containing a <code>:=</code> are defined in ECL as attribute definitions. They do not denote an action; rather a definition of a term. Thus, logically, an ECL program can be read: "bottom to top"

Line 44 ⟶ 45:

What is an SD?

<sourcesyntaxhighlight lang="ecl">

SD := SORT(D,Value);

</syntaxhighlight>

</source>

SD is a D that has been sorted by ‘Value’

What is a D?

<sourcesyntaxhighlight lang="ecl">

D := DATASET([{'ECL'},{'Declarative'},{'Data'},{'Centric'},{'Programming'},{'Language'}],{STRING Value;});

</syntaxhighlight>

</source>

D is a dataset with one column labeled ‘Value’ and containing the following list of data.

=== ECL primitives ===

ECL primitives that act upon datasets include: SORT, ROLLUP, DEDUP, ITERATE, PROJECT, JOIN, NORMALIZE, DENORMALIZE, PARSE, CHOSEN, ENTH, TOPN, DISTRIBUTE

=== ECL encapsulation ===

Whilst ECL is terse and LexisNexis claims that 1 line of ECL is roughly equivalent to 120 lines of C++, it still has significant support for large scale programming including data encapsulation and code re-use. The constructs available include: MODULE, FUNCTION, FUNCTIONMACRO, INTERFACE, MACRO, EXPORT, SHARED

=== Support for Parallelism in ECL ===

Line 65 ⟶ 66:

=== Comparison to Map-Reduce ===

The Hadoop Map-Reduce paradigm actually consists of three phases which correlate to ECL primitives as follows.

{| class="wikitable"

|-

Line 78 ⟶ 79:

| SHUFFLE (Phase 1)

| DISTRIBUTE(,HASH(KeyValue))

| The records from the mapper are distributed dependentdepending upon the KEY value

|-

| SHUFFLE (Phase 2)

Line 86 ⟶ 87:

| REDUCE

| ROLLUP(,Key,LOCAL)

| The records for a particular KEY value are now combined together

|}

Line 95 ⟶ 96:

== External links ==

* [http://rosettacode.org/wiki/ECL Rosetta Code ECL category]

* [https://hpccsystems.com/training/documentation/ecl-language-reference/html ECL Language Reference] {{Webarchive|url=https://web.archive.org/web/20210116135748/https://hpccsystems.com/training/documentation/ecl-language-reference/html |date=2021-01-16 }}

* [https://www.nytimes.com/2008/02/21/technology/21iht-reed.4.10279549.html Reed Elsevier to acquire ChoicePoint for $3.6 billion]

* [https://www.bloomberg.com/apps/news?pid=newsarchive&sid=aBuqYZDOSPL4&refer=uk Reed Elsevier's LexisNexis Buys Seisint for $775 Mln]

* [https://archive.today/20130201091208/http://www.reuters.com/finance/stocks/keyDevelopments?symbol=ENL&pn=15 Reed Elsevier]

[[Category:Declarative programming languages]]

[[Category:Data-centric programming languages]]

[[Category:Big data]]

[[Category:Statically typed programming languages]]