# Do EDCG have a predicate indicator notation?

**URL:** <https://swi-prolog.discourse.group/t/do-edcg-have-a-predicate-indicator-notation/2018>\
**Category:** Help!\
**Tags:** edcg\
**Created:** [March 16, 2020, 12:14pm UTC](https://swi-prolog.discourse.group/t/do-edcg-have-a-predicate-indicator-notation/2018 "2020-03-16T12:14:56Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![EricGT](https://avatars.discourse-cdn.com/v4/letter/e/f1d935/32.png) [@EricGT](https://swi-prolog.discourse.group/u/EricGT)\
**Post date:** [March 16, 2020, 12:14pm UTC](https://swi-prolog.discourse.group/t/do-edcg-have-a-predicate-indicator-notation/2018/1 "2020-03-16T12:14:56Z")

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Regular Prolog predicates (`:-`) have an indicator notation of

`<name>/<arity>` ([ref](https://www.swi-prolog.org/pldoc/man?section=preddesc))

or with a module

`<module>:<name>/arity`

DCG (`-->`) have an indicator notation of

`<name>//<arity>`

* * *

When using EDCG (`-->>`) is there a special notation for them?

I am thinking of something like

`hex_dump/4 + input/2 + output/2`

where `/4` is the visible arguments and `input/2` is for the hidden `input` accumulator and `output/2` is for the hidden `output` accumulator.

I have not used the single arguments (pass\_info/3) of EDCG yet, but am thinking it will obviously be like

`hex_dump/4 + input/2 + output/2 + value_spacing/1 + section_spacing/1`

* * *

> **Personal Notes**
>
> [Modes used in the Commons Library](http://prolog-commons.org/PrologCommons.html/commons_modes_doc.html)

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**Author:** ![peter.ludemann](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/peter.ludemann/32/48_2.png) [@peter.ludemann](https://swi-prolog.discourse.group/u/peter.ludemann)\
**Post date:** [March 16, 2020, 7:40pm UTC](https://swi-prolog.discourse.group/t/do-edcg-have-a-predicate-indicator-notation/2018/2 "2020-03-16T19:40:39Z")

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I don’t think that there’s a standard notation. I’ve been using `name//<arity>[accum1,accum2,...]` but the regular tools don’t like that. (The list of accumulators is the same as used by `edcg:pred_info/3`.)