Category:CafeOBJ: Difference between revisions

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==Basic Information==
==Basic Information==
CafeOBJ is a algebraic specification language.
CafeOBJ is a algebraic specification language.
It has an executable sub-language which is broadly similar to Haskell or ML.
It has an executable sub-language which is broadly similar to a first order subset of Haskell or ML. CafeOBJ has many advanced features including: multiple logics, flexible mix-fix syntax, powerful and clear typing system with ordered sorts, parametric modules and views for instantiating the parameters, and module expressions, and more.
⚫
CafeOBJ is primarily a first order specification language which can also be used as a functional programming language. Being first order, there are no higher order functions such as map. Higher order functions can be simulated to some degree using paramterized modules. CafeOBJ includes a minimal library of basic types such as natural numbers, integers, floating point number, and character strings.
CafeOBJ has many advanced features including: multiple logics, flexible mix-fix syntax, powerful and clear typing system with ordered sorts, parametric modules and views for instantiating the parameters, and module expressions, and more.
⚫
CafeOBJ is primarily a first order specification language which can also be used as a functional programming language. Being first order, there are no higher order functions such as map. Higher order functions can be simulated to some degree using paramterized modules. CafeOBJ includes minimal library of basic types such as natural numbers, integers, floating point number, and character string.
There are no libraries for arrays, lists, trees, or graphs, hence the user written list below. Many of CafeOBJ features are inherited from [http://en.wikipedia.org/wiki/OBJ3 OBJ3]
There are no libraries for arrays, lists, trees, or graphs, hence the user written list below. Many of CafeOBJ features are inherited from [http://en.wikipedia.org/wiki/OBJ3 OBJ3]


[https://cafeobj.org/ Download] ,
[https://cafeobj.org/ Download] ,
[https://cafeobj.org/intro/en/ Introduction] ,
[https://cafeobj.org/intro/en/ Introduction] ,
[https://www.preining.info/blog/2018/04/specification-and-verification-of-software-with-cafeobj-part-1-introducing-cafeobj/ Tutorial]
[https://www.preining.info/blog/2018/04/specification-and-verification-of-software-with-cafeobj-part-1-introducing-cafeobj/ Tutorial] ,
[http://www.jaist.ac.jp/~ogata/lecture/i217/ Lectures] ,
[http://www.jaist.ac.jp/~ogata/lecture/i217/ Lectures].
[https://equational.wordpress.com/2016/09/07/algebraic-specification/#more-4/ Blog].
[https://www.youtube.com/watch?v=x9EImMXN6Rk Video-1] ,


⚫
===Examples===


<syntaxhighlight lang="$CafeOBJ">



⚫
===Examples===
<lang CafeOB>
-- Text file called say Hello.cafe ,contains the following
-- Text file called say Hello.cafe ,contains the following
mod! HELLO-WORLD {
mod! HELLO-WORLD {
Line 34: Line 30:
reduce hello .
reduce hello .
-- Gives ("Hello World"):String
-- Gives ("Hello World"):String
</syntaxhighlight >
</lang>


See [https://rosettacode.org/wiki/Sorting_algorithms/Quicksort#CafeOBJ] for more traditional quicksort
Below is a idiosyncratic sorting program. See [https://rosettacode.org/wiki/Sorting_algorithms/Quicksort#CafeOBJ] for more traditional quicksort program.

<syntaxhighlight lang="$CafeOBJ">
-- Run in CafeOBJ 1.5.5(PigNose0.99)
-- System settings
full reset
set step off
set print mode :fancy
set stats off
set verbose off
set quiet on


<lang CafeOB>
-- Here is a one line sorting program.
-- Here is a one line sorting program.
mod! SORTING-NAT {
mod! SORTING-NAT {
pr(NAT)
pr(NAT) -- import
[Nat < List ]
[Nat < List ] -- Nat is a sub-sort of List
-- Simple list structure
-- Simple space seperated list structure
op nil : -> List
op nil : -> List
op _._ : List List -> List { assoc id: nil }
op __ : List List -> List { assoc id: nil }
⚫
vars N N' : Nat
⚫
-- The program is in the form of a single conditional equation, which will swap N and N' if N is larger or equal to N'.
⚫
-- There is no need for an intermediate variable to do the swap.
⚫
ceq [swap] : (N N') = (N' N) if N' < N and (N =/= N').


⚫
vars N N' : Nat
-- A very short sorting program using one transition equation in POA logic, which is a type of rewrite logic.
⚫
-- The program is in the form of a condition transition, which will swap N and N' if N is larger or equal to N'.
⚫
-- This is a equation in POA logic so there is no need for an intermediate variable to do the swap.
⚫
ctrans [swap] : (N . N') => (N' . N) if N' <= N .
}
}

**> Sorting natural numbers using exec command
**> Sorting natural numbers using reduce command
open SORTING-NAT
open SORTING-NAT .
exec (3 . 2 . 1) .
red (3 2 1) .
--> Gives (1 . 2 . 3):List
--> Gives (1 2 3):List
red (9 3 6 12 1 20) .
**> We can consider sorting as a path through the state space of the permutations of N numbers.
--> Gives (1 3 6 9 12 20):List
**> There are N! permutations only one of which is sorted.
**> Sorting natural numbers using search command
**> we can use (show path N) with this command, where N is the number of possible states.
red (3 . 2 . 1) =(1,1)=>* (1 . 2 . 3) .
red (3 . 2 . 1) =(1,2)=>* (1 . 2 . 3) .
red (3 . 2 . 1) =(1,3)=>* (1 . 2 . 3) .
**> search for any number of solutions at any depth
red (3 . 2 . 1) =(*,*)=>* (1 . 2 . 3) .
**> print the transitions from initial to goal state
show path 5
eof
eof
</syntaxhighlight>
</lang>

Latest revision as of 13:30, 12 October 2022

Language
CafeOBJ
This programming language may be used to instruct a computer to perform a task.
See Also:


Listed below are all of the tasks on Rosetta Code which have been solved using CafeOBJ.

Basic Information

CafeOBJ is a algebraic specification language. It has an executable sub-language which is broadly similar to a first order subset of Haskell or ML. CafeOBJ has many advanced features including: multiple logics, flexible mix-fix syntax, powerful and clear typing system with ordered sorts, parametric modules and views for instantiating the parameters, and module expressions, and more. CafeOBJ is primarily a first order specification language which can also be used as a functional programming language. Being first order, there are no higher order functions such as map. Higher order functions can be simulated to some degree using paramterized modules. CafeOBJ includes a minimal library of basic types such as natural numbers, integers, floating point number, and character strings. There are no libraries for arrays, lists, trees, or graphs, hence the user written list below. Many of CafeOBJ features are inherited from OBJ3

Download , Introduction , Tutorial , Lectures. Blog.

Examples

-- Text file called say Hello.cafe ,contains the following
mod! HELLO-WORLD {
pr(STRING)
op hello : -> String
eq hello = "Hello World" .
}
-- Start CafeOBJ interactive session at command line
--> cafeobj
-- Bring *in* the file at CafeOBJ prompt 
in hello.cafe
-- Open the HELLO-WORLD module
open HELLO-WORLD
-- Execute with the reduce command
reduce hello .  
-- Gives ("Hello World"):String

Below is a idiosyncratic sorting program. See [1] for more traditional quicksort program. 

-- Run in CafeOBJ 1.5.5(PigNose0.99)
-- System settings
full reset
set step off
set print mode :fancy
set stats off
set verbose off
set quiet on

-- Here is a one line sorting program.
mod! SORTING-NAT {
pr(NAT) -- import
[Nat < List ] -- Nat is a sub-sort of List
-- Simple space seperated list structure
op  nil : -> List
op __ : List List -> List { assoc id: nil }
 
vars N N' : Nat
-- The program is in the form of a single conditional equation, which will swap N and N' if N is larger or equal to N'.
-- There is no need for an intermediate variable to do the swap.
ceq [swap] : (N  N') = (N'  N) if N' < N and (N =/= N').

}
 
**> Sorting natural numbers using reduce  command
open SORTING-NAT .
red (3  2  1) .
--> Gives (1 2 3):List
red (9 3 6 12 1 20) .
--> Gives (1 3 6 9 12 20):List
eof

Pages in category "CafeOBJ"

The following 3 pages are in this category, out of 3 total.

D

R

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