Pseudo-Code

Interpreter for course - Analysis of Programing Languagues. The idea of this language is based on simple fact, that all algorithms are already written in some kind of pseudo code, so why do not write a simple interpreter for that.

Build

To build this interpreter just run bash script ./make.bash

Requirements

For building is necessary flex and bison. Current code is supported only by GNU/Linux and Mac OS X operating systems.

Usage

The starting point of every code is the main function, which is mandatory.

Basic Operations

Like every language even ours Pseudo-Code supports basic arithmetic operation as +-/*<>!=. Each variable must be defined this way A and currently we are supporting only integers.

Arrays

Arrays are indexed from 1 and can be defined by the following way

func main ()
  A = 1,2,3
end func

Access or modify array elements is possible by the usual way

func main ()
  A = 1,2,3
  print A[1] //1
  A[1] = 99 
  print A[1] //99
end func 

Loops

This language support only one type of loops. It's basic for loops with syntax like that

func main ()
 for i from 1 to N do
    print i
 end for
end func

Conditions

This language support just basic if and else condtion with syntax like that

func main ()
  if A > B then      
      //DO SOMETHING
  end if
end func

or example of if-else statement

func main ()
  if A > B then      
      //DO SOMETHING
  else
      //DO SOMETHING ELSE
  end if
end func

Functions

Functions are defined just with special keyword func and every function must be ended with function ending end func. Return variable has the same name as function. Here is a simple example

func foo( A )
    foo = A + 1
end func

Built-in functions

The following functions are natively built in Pseudo-Code

void swap(var, var)

func main ()
  a = 5
  b = 6
  swap(a, b)
  print a // 6
  print b // 5 
end func

int len(array/variable)

func main ()
  A = 1,2,3,4,5,6
  print len(A) // 6
  B = 0
  print len(B) // 1
end func

Examples

As for every language let's start with the most important

func main ()
  print 'Hello World!'
end func

Example of calling function with an argument

func foo (c)
  print c
end func

func main ()
  c = 10
  foo(c) // 10
end func

Next example is simple bubble sort on array of integers

func bubblesort( a )
	N = len(a)
    for i from 1 to N do
        for j from 1 to N - 1 do
           if a[j] > a[j + 1] then
              swap( a[j], a[j + 1] )
           end if
        end if
    end for   
end func