CAIE Code (cpc)

the CAIE Pseudocode Interpreter

中文 | English

Installation and Update

Online Version

Installation Preliminaries

1. Have python3 installed on your computer.

It is suggested to use pypy3 to achieve the best efficiency.

1. Have git installed on your computer. If you do not know what git is, see https://git-scm.com/downloads.

For macOS users ensure you installed Command Line Tools for Xcode.

3. cargo if you want to compile manually

Installation

0. For macOS users, you can install directly using CAIE_Code_Installer.dmg from the releases page.

For other users...

1. Clone the project to your computer using git clone https://github.com/iewnfod/CAIE_Code.git.

2. Enter the project folder: cd CAIE_Code.

3. The executable programs are in bin/ folder. You may directly run or consider adding bin/ to your PATH.

4. If you want to compile manually:

• macOS: run build.sh
• Windows: run build.ps1

5. If you want to see the manual page from man command, you should consider link the manual file man/cpc.1 to your MANPATH.

   For example(Linux): sudo ln -f ./man/cpc.1 /your/man/path.

6. If you cannot execute the complied files, please submit the problems on our issue page.

Update

• If you followed the instructions and used git or PKG to install cpc, you can update easily using cpc -u.

• An auto-update feature is introduced after dc0cd71 to automatically detect updates once a week.

• Otherwise, you should manually re-install the whole project.

Usage

cpc [filepath] [options]

It runs the entire file if filepath is provided, otherwise, it enters playground mode.

Options

Config

• remote

  • github: Use GitHub as the update source. This source is always the latest.
  • gitee: Use Gitee as the update source, which might be slower than Github.

• branch

  • stable: Updates are slow, but the most stable.
  • nightly: This branch will update once a day. Early adopters can try this branch, please actively report the issue.
  • dev: The latest version of CPC may contain many untested functions.

  This setting needs to be run cpc -u once for it to take effect.

  In a developer mod, your remote will not be changed by config and the branch will be locked in dev.

• auto-update

  • true：Enable auto update.
  • false：Disable auto update.

• last-auto-update All non-negative real numbers are accepted and automatically updated by the system.

• interval-update All non-negative integers, in seconds, are accepted as the automatic update interval.

• recursion-limit(rl) all integer number as the recursion depth limit of the interpreter.

• integrity-protection

  • true: Enable integrity protection.
  • false: Disable integrity protection.

  Integrity Protection prevent any accidental or malicious modification of the interpreter.

  This protection will be automatically disabled in developer mode.

• dev

  • true: Enable developer mode.
  • false: Disable developer mode.

• Developer Options

  • dev.simulate-update
    • true: Enable simulation updates
    • false: Disable simulation updates

FAQs

Import Error

Please try to install all Python packages manually using pip install -r requirements.txt

Import Error after I manually installed packages

The program will automatically detect pypy3 when available and use it to interpret pseudocode because it has better efficiency.

If you have pypy3 installed you should install manually using pypy3 -m pip install -r requirements.txt

Incorrect <up>, <down>, <left>, <right> key actions when in playground mode

You should retry pip install readline or pip install gnureadline.

OSError when launching

Enter the directory of this project, and run

rm -rf .cpc_history
cpc -u

Other problems?

If it still fails after re-installation, please report it to us on the issue page.

Efficiency test

Test Environment

• machine: 2020 MacBook Pro
• processor: Apple M1
• RAM: 8GB
• Cores: 8 (4 efficient, 4 performance)
• OS: macOS 14.1.1 (23B81)
• Python version: PyPy 3.9.16

Basic Tests

• assignment: 1200w/s

DECLARE a : INTEGER
FOR i <- 1 TO 12000000
    a <- i
NEXT i

• explicit conversion and assignment: 760w/s

DECLARE a : STRING
FOR i <- 1 TO 7600000
    a <- STRING(i)
NEXT i

• implicit conversion and assignment: 1000w/s

DECLARE a : STRING
FOR i <- 1 TO 10000000
    a <- i
NEXT i

• print to terminal: 65w/s

FOR i <- 1 TO 650000
    OUTPUT i
NEXT i

Computation Tests

• generating 100k randoms and shell sorting: about 3.5s

Standards

Basic Standards

• use camelCase naming
• use .cpc as the file suffix
• use utf-8 encoding
• all reserved words are in upper case
• the program is case-sensitive
• use // to comment code

Features

Most syntax follows the pseudocode standard of CAIE.

However, indentation is suggested but not compulsory.

Each statement following CASE statement must end with a ;, semicolon.

Basic Data Types

The following items give the DATATYPE, its description, and the default value set when defined in brackets.

• INTEGER integer, whole number (0)

  1
  2
  123
  -123
  

• REAL float-point number (0.0)

  1.1
  0.1
  -12.1233
  

• CHAR one single character ('')

  '1'
  '!'
  'd'
  

• STRING string ("")

  "Hello"
  "World"
  "!"
  

• BOOLEAN boolean (FALSE)

  TRUE
  FALSE
  

• DATE date (current date)

  25/07/2023
  10/12/2012
  

None is a null datatype returned by some special functions. it should not be used in normal coding and cannot be declared.

Syntax Definitions

1. Variables and constants

   • Declare variables

     DECLARE <identifier> : <data type>
     DECLARE <identifier> : ARRAY [<lower>:<upper>, ...] OF <data type>
     

   • Declare constants

     CONSTANT <identifier> = <value>
     

   • Assignment

     <identifier> <- <value>
     <identifier>[<index>, ...] <- <value>
     

     Pseudocode uses <- instead of =.

2. I/O

   • Input

     INPUT <identifier>
     

   • Output

     OUTPUT <value>, ...
     

3. Operations

   • + addition
   • - subtraction
   • * multiplication
   • / division
   • > greater than
   • >= greater than or equal to
   • < smaller than
   • <= smaller than or equal to
   • = equal (NOT AN ASSIGNMENT STATEMENT)
   • <> not equal
   • & conglomerate strings
   • MOD modulus, find the remainder
   • DIV integer division

4. Logic operations

   • AND
   • OR
   • NOT

5. Conditional statements

   • IF statements

     IF <condition> THEN
         <statements>
     ENDIF
     
     IF <condition> THEN
         <statements>
     ELSE
         <statements>
     ENDIF
     

   • CASE statements

     IMPORTANT: official standards do not have semicolons ; here

     CASE OF <identifier>
         <value> : <statements>;
         <value> : <statements>;
         ...
         OTHERWISE : <statements>;
     ENDCASE
     

6. Loop statements

   • FOR loop

     FOR <identifier> <- <value> TO <value>
         <statements>
     NEXT <identifier>
     

   • REPEAT loop

     REPEAT
         <statements>
     UNTIL <condition>
     

   • WHILE loop

     WHILE <condition>
         <statements>
     ENDWHILE
     

7. functions

   • functions without a return value (procedure)

     PROCEDURE <identifier> ()
         <statements>
     ENDPROCEDURE
     
     PROCEDURE <identifier> (<param> : <data type>, ...)
         <statements>
     ENDPROCEDURE
     

   • call a procedure

     CALL <identifier> ()
     
     CALL <identifier> (<value>, ...)
     

   • functions with return values

     FUNCTION <identifier> RETURNS <data type>
         <statements>
         RETURN <value>
     ENDFUNCTION
     
     FUNCTION <identifier> (<param> : <data type>, ...) RETURNS <data type>
         <statements>
         RETURN <value>
     ENDFUNCTION
     

   • call a function with return values

     <identifier> ()
     
     <identifier> (<value>, ...)
     

   • Before the parameters of those sub-routines, you can use BYREF or BYVAL to force the program to pass those parameters by reference or by-value respectively. If no BYREF nor BYVAL is given, the program will follow the prior parameter. If the program cannot find a clear indication it will, by default pass parameters by value.
     • If you explicitly define the data types of the array passed BYVAL the program will implicitly convert to the designated data type; the program will not convert data types when passed BYREF.
     • BYREF : pass the reference of a variable
     • BYVAL : pass a copy of the variable

8. File I/O

   • open a file

     OPENFILE <file path> FOR <file mode>
     

   • read a file

     READFILE <file path>, <variable>
     

   • write to a file

     WRITEFILE <file path>, <data>
     

   • close a file

     CLOSEFILE <file path>
     

   • locate in the file

     SEEK <file path>, <address>
     

   • File Mode
     1. READ
     2. WRITE
     3. APPEND
     4. RANDOM

9. Self-defined data types

   • enumerate type

     TYPE <identifier> = (<identifier>, ...)
     

   • pointer type

     TYPE <identifier> = ^<data type>
     

   • records(classes)

   In this case, the program will not check the data types when assigning a variable of this type to another. The program will assign the other variable as the reference for this one. TYPE <identifier> <statements> ENDTYPE

10. Object Oriented Programme

    • define an object

      CLASS <identifier>
          PUBLIC PROCEDURE NEW (<params>)
              <statements>
          ENDPROCEDURE
          <statements>
      ENDCLASS
      

    • private or public variable

      PRIVATE <identifier> : <type>
      PUBLIC <identifier> : <type>
      

    • private or public procedure and function

      PRIVATE PROCEDURE <identifier> (<params>)
          <statements>
      ENDPROCEDURE
      
      PUBLIC PROCEDURE <identifier> (<params>)
          <statements>
      ENDPROCEDURE
      
      PRIVATE FUNCTION <identifier> (<params>) RETURNS <type>
          <statements>
      ENDFUNCTION
      
      PUBLIC FUNCTION <identifier> (<params>) RETURNS <type>
          <statements>
      ENDFUNCTION
      

    • create an object

      NEW <identifier> (<values>)
      

    If you do not sign a variable or procedure or function explicitly, it will be public by default.

Special Syntax of CPC Interpreter

• delete a variable or constant on RAM

  DELETE <identifier>
  

• do nothing

  PASS
  

• import CPC files

  IMPORT <expression>
  

  expression here should be a string within double quotes. There is no isolation between the imported file and the main file. Identifiers may collide. It is suggested to use the Import function to import a package instead.

  CONSTANT <identifier> = Import("<path to import file>")
  

Built-in Functions from CAIE Standard

• LEFT(ThisString : STRING, x : INTEGER) RETURNS STRING

  $ LEFT("ABCDEFGH", 3)
  "ABC"
  

• RIGHT(ThisString : STRING, x : INTEGER) RETURNS STRING

  $ RIGHT("ABCDEFGH", 3)
  "FGH"
  

• LENGTH(ThisString : STRING) RETURNS INTEGER

  $ LENGTH("Happy Days")
  10
  

• MID(ThisString : STRING, x : INTEGER, y : INTEGER) RETURNS STRING

  $ MID("ABCDEFGH", 2, 3)
  "BCD"
  

• LCASE(ThisChar : CHAR) RETURNS CHAR

Decrapricated since 2023 $ LCASE('W') 'w'

• UCASE(ThisChar : CHAR) RETURNS CHAR

Decrapricated since 2023 $ UCASE('h') 'H'

• TO_UPPER(x : <datatype>) RETURNS <datatype>

may be CHAR or STRING

  $ TO_UPPER("hello")
  "HELLO"

  $ TO_UPPER('a')
  'A'

• TO_LOWER(x : <datatype>) RETURNS <datatype>

may be CHAR or STRING

  $ TO_LOWER("HELLO")
  "hello"

  $ TO_LOWER('A')
  'a'

• INT(x : REAL) RETURNS INTEGER

  $ INT(27.5415)
  27
  

• RAND(x : INTEGER) RETURNS REAL

  $ RAND(87)
  35.43
  

• EOF(file_path : STRING) RETURNS BOOLEAN
• POW(x: REAL, y: REAL) RETURNS REAL
• DAY(ThisDate : DATE) RETURNS INTEGER

    $ DAY(25/07/2023)
    25
  

• MONTH(ThisDate : DATE) RETURNS INTEGER

    $ MONTH(25/07/2023)
    7
  

• YEAR(ThisDate : DATE) RETURNS INTEGER

    $ YEAR(12/12/2005)
    2005
  

• DAYINDEX(ThisDate : DATE) RETURNS INTEGER

Where Sunday = 1, Monday = 2 etc

  $ DAYINDEX(25/03/2024)
  2

• SETDATE(day : INTEGER, month : INTEGER, year : INTEGER) RETURNS DATE

    $ SETDATE(25, 03, 2024)
    25/03/2024
  

• TODAY() RETURNS DATE

    $ TODAY()
    25/03/2024
  

Built-in Functions of this Interpreter

These functions are fairly useful, but they are not included in the CAIE standard.

• EXIT(code : INTEGER): exit the program with the exit code code. Defalt exit code is 0.

• ROUND(x : REAL, decimalPlace : INTEGER): round the float-point number x to some decimal place. The default decimal place is 0(to the nearest whole number).

• PYTHON(code : STRING, *args) is a Python interface. You can pass any Python statements into code and the program will run it in standard Python. the return value of this function is the value of variable _result in the Python code.

  Example:

  > DECLARE a : INTEGER
  > a <- 0
  > OUTPUT PYTHON("_result=a+1", a)
  1
  

  if the Python code does not assign a value to _result, the function will return None. you must pass all variables used in the Python code in *args, otherwise, it will not run correctly.

• VARTYPE(v) is an interface to get the type of v and return it as a string.

• ANY is a type that used to allow some unknown type data.

• For more non-official scripts, please see scripts.

Targets

Version 0.1.x Target

• [ ] Implement all features provided by official document.
• [ ] Increase the stability for running to achieve a relatively useable situation.

Version 0.2.x Target

• [ ] Give the kernel a great update and optimization.
• [ ] Implement a high performance virtual machine to run. (Similar as the solution of Java)

Version 0.3.x Target

• [ ] Allow building into executable binary file.

Long-term Targets

• [ ] Provide more packages for use.
• [ ] Increase running speed and stability.
• [ ] Implement bootstrap.

Sponsors

Author and Contributors