C-- Script

C-- Script is a simple script language.

Comments

Comments are C-style, that is, in /* */ pairs.

Consts

There are three types of const number in C-- Script. They are all integers. No other data types are supported. They are

• Decimal int, like 1234, 5678, 90
• Hexadecimal int, like 0x1A, 0X2B
• Binary int, like 0b11, 0B1010

There is also const string in C-- Script. To make a string, put text between a pair of double quotation marks, like "Hello, World!". Escape characters as in a C-style string are not supported.

Varibles

Rules for varible names are like in C language, except that @ and \ can be used in varible names.

Varibles are defined when they appear for the first time. The type of a varible is determined by the value assigned to it. If a varible is never assigned a value, its type is UNDEF. According to the values assigned are integers or strings, varibles can be INT or STR type, which are simple types.

A varible can also be VEC type, that means there are a series of values associated with the varible, which are indexed by integers. Each of the value can also be of any type. For example

a = @
/* @ is a built-in special varible. 
 * To make a varible VEC type, you should assign @ to it.
 */
a[0] = 1; a[1] = "Hello"; a[2] = @
a[2][0] = 2; a[2, 1] = 3 /* both are supported */

A varible can also be MAP type, that means there are a series of values associated with the varible, which are indexed by strings. Each of the value can also be any type. For example

a = \
/* \ is a built-in special varible.
 * To make a varible MAP type, you should assign \ to it.
 */
a["first"] = 1; a.second = 2 /* both are supported */

Expressions and statements

Expressions are all like in C language if the operators are supported. The unsupported operators are:

• Post self increment ++ and post self decrement --
• Address & and derefrence *
• Ternary operator ? :

Any expressions can be statements. Statements are ended if a line is ended. You can use ; to seperate several statements in a single line, but ; is not required for a statement.

Branch structure

Using ? : $ to make a branch structure, like

a < 10 ? ++num1 : ++num2 $

That means, if a is less than 10, the value of num1 is increased by one, otherwise the value of num2 is increased by one.

Loop structure

Using { # } to make a loop structure, like

i = 0 { i < 10 ?:#$ ++i }

That means, i is increased by one, starting from 0; if i is not less than 10, the loop ends. The codes between { and } are executed repeatedly, and # always makes it jump out the loop to the code after }.

Functions

There are only built-in functions, no user-defined functions are supported. Functions take unlimited number of parameters and return a value, like

_pw(3, a, a+b, (a+b)*c)

Currently the built-in functions are:

• _p(): to output the parameters
• _pln(): to output a line break
• _pw(): to output the parameters except the first one. the first parameter is used to set the output width

Command Line

In the command line interface, you can type in any codes, which are executed when you press Enter. There are also a few commands you can use, but they are not part of C-- Script. They are

• clear: to clear all user-defined varibles
• ids: to show all the varibles
• funs: to show all the functions
• run filename: to look for a file named filename.cmm, read it in and execute it
• exit: exit the program