minscript - a simple Java/C++ like script interpreter

Minscript is an object oriented scripting language. The scripting language is a small subset of the C++ language. It has even more in common with Java than with C++. The aim of the script language is not to execute all possible C++ programs, instead every valid minscript program should compile with a C++ compiler. Have a look at the sample script to get an impression of the syntax of the scripting language.

The main features of the minscript language are:

• preprocessor (#define's and #ifdef's are possible!)
• buildin types: bool, char, int, double, string
• typedef
• expressions
• statements: if/else, for, while, do/while, switch
• functions
• function overloading
• classes and structs
• virtual methods
• multiple inheritance
• scope mechanism in blocks
• template-classes
• references and pointers (in a very simple way, no pointer arithmetic possible)
• C/C++ API
• multiplattform support, runs on: Windows, Linux, OS/2
• a lot of buildin functions
• some language extensions

Not supported features of the C++ language are:

• no extern declarations of methods, all methods have to be declared inline !
• no operator overloading
• no template functions
• no templates in typedefs, use #define's
• no explicit casts (the buildin types are casted automatically)
• no iostream's
• no goto's
• no default arguments in functions or methods (example: int f( int i = 0 ) {})
• no multidimensional arrays (example: int aArray[4][4];)
• no pointer arithmetic (example: int * p; ... p = p+1;)

Features of the minscript program package are:

• preprocessor
• external functions in loadable modules
• stubcode-generator for automatic creation of stubcode needed for the registration of external functions in the interperter
• wrappercode-generator for automatic creation of wrapper-classes
• test scripts to validate the minscript-interpreter against a c++ compiler (see: specs/auto_test.ic)

Known bugs of minscript are:

• #if defined( 1 ) is false
• const modifier of methods is not verified
• every virtual method has to be declared with the virtual keyword, even if the method is declared as virtual in the baseclass
• for( int i=0; i<10; i++ ) {} doesn't work, you can not declare variables in the for-statement
• long, short, unsigned doesn't work, use long int, short int, unsigned int
• case-labels don't have to be constant!
• arrays can not created dynamically (example: int * pArray = new int [8];)
• aObj.f() works even if the class of aObj has no method with name f() but a function with name f() exists
• there are some problems with virtual destructors or references for objects with virtual methods, see test_classes.ic
• access to private member variables of classes is possible
• not all keywords have the same meaning as in C++: extern, static, const
• you could write valid minscript programs which will not compile with a C++ compiler
• not all templates features are supported
• there are a lot of unknown bugs!

Open issues:

• Add automated unit tests

Platforms

Minscript is written in (plain) C++ and therefore supports (in principle) all platforms which have a C++ compiler.

Minscript was successfully compiled on Windows, Mac OS X, Android, Linux (including the Raspberry Pi) and OS/2.

• Windows
• MacOS, Linux and Android

Sample script

Sample1.ic:

/* 
    A simple sample script with some features
*/

#define MAX	512

const string c_sString = "C++ is nice.";

// a simple class to test the scope mechanismus 
class MyTestClass
{
public:
    // allways inlining !
    MyTestClass( int i )
    {
        __println( "MyTestClass::MyTestClass(int) i="+i );
        m_i = i;
    }
    ~MyTestClass()
    {
        __println( "MyTestClass::~MyTestClass(int) i="+m_i );
    }

    int f()
    {
        return m_i*m_i;
    }
private:
    int    m_i;
};

void TestFunction( string s, double d )
{
    double dResult = d * d - 4.5;
    string sTemp;

    /* create a result string */
    sTemp = s + " Result="+dResult;

    // now print the string
    __println( sTemp );
}

int main()
{
    TestFunction( "Hello minscript world ! This is a function.", 9.123 );

    __println( "test scope..." );
    {
        MyTestClass aObj( 7 );

        __println( "aObj.f() = " + aObj.f() );
    }
    __println( "test scope done." );

    return 0;
}

#ifdef __MINSCRIPT__
main();
#endif

The output of this script is (run: minscript Sample1.ic):

Hello minscript world ! This is a function. Result=78.729129
test scope...
MyTestClass::MyTestClass(int) i=7
aObj.f() = 49
MyTestClass::~MyTestClass(int) i=7
test scope done.

Buildin functions:

int __print( string s )                         prints a string to the standard output stream
int __println( string s )                       prints a string to the standard output stream and appends a new line
int __errorln( string s )                       prints a string to the error stream and appends a new line
void __sleep( int iDelay )                      suspends the program execution for iDelay ms
int __loaddll( string s )                       load the module with a given name, returns the handle for the module
int __unloaddll( int hDll )                     frees the module
long clockms()                                  return the clock value in ms

int sizeof( expression )                        returns the size of the expression type 

int fopen( string sFileName, string sMode )     opens a file in sMode (usual file-modes from <stdio.h>)
int fclose( int hFile )                         closes a file
int feof( int hFile )                           checks a file for end-of-file status
int ferror( int hFile )                         checks a file for error status
int fputs( string sText, int hFile )            writes a string into a file
int fgets( string & sText, int hFile )          reads a string from a file


int current_time_hour()                         return the hour value of the current time
int current_time_minute()                       return the minute value of the current time
int current_time_second()                       return the second value of the current time
int current_date_year()                         return the year of the current date
int current_date_month()                        return the month of the current date
int current_date_day()                          return the day of the current date
    
string getenv( string sName )                   reads an environment variable
int putenv( string sNameValue )                 writes an environment variable
void exit( int iValue )                         exits the program imediately with the exit-code iValue
int system( string sCmd )                       system call, runs (synchroniously) the command in the string sCmd
bool splitpath( string sFullPath, string & sDrive, string & sPath, string & sName, string & sExt )
                                                splits a given path in substrings for drive, path, name and extension

int string_read()                               reads a string from the standard input and returns the string
int string_npos()                               returns a integer constant to show that the find-function was not successfull
int string_length( string s )                   returns the length of the string
char string_at( string s, int iPos )            returns the character in the string at the given position
string string_setchar( string s, int iPos, char ch )            returns a string with the changed character at the given position 
int string_find( string s, string sSearch )     returns the position of the sSerach-string in the string s, returns string_npos() if the search string was not found
string string_substr( string s, int iStartPos, int iLength )    returns a substring of the given string
string string_insert( string s, int iPos, string sInsert )      returns a string in which the sInsert string is inserted in the string s
string string_erase( string s, int iPos, int iLength )          returns a string in which the given range is erased
string string_replace( string s, int iPos, int iLength, string sReplace )    returns a string in which a part of the string is replaced by another string

double fabs( double d )                         returns absolute value of d
double sin( double d )                          returns the sinus of d
double asin( double d )                         returns the arcus-sinus of d
double sinh( double d )                         returns the sinus hyperbolicus of d
double cos( double d )                          returns the cosinus of d 
double acos( double d )                         returns the arcus-cosinus of d 
double cosh( double d )                         returns the cosinus hyperbolicus of d 
double tan( double d )                          returns the tangens of d
double atan( double d )                         returns the arcus-tangens of d
double atan2( double d1, double d2 )            returns the arcus-tangens of d 
double tanh( double d )                         returns the tanges hyperbolicus of d
double sqrt( double d )                         returns the squareroot of d
double exp( double d )                          returns the e the power of d
double log( double d )                          returns the logarithm of d
double log10( double d )                        returns the logarithm for base 10 of d
double pow( double d1, double d2 )              returns the power of d1 by d2

Language extensions

__exists variablename        verifys if a variable with the given name exists
__dbghalt expression         sets an user brakepoint, the execution of the script will be stoped when this statement will be reached.
                             Dumps all functions and methods if expression has the value "fcn".
typeof variablename          prints the type of the variable

Predefined symbols of the preprocessor

__MINSCRIPT__       is defined if the script is executed by the minscript application
__STDC__            is allways set
__cplusplus         is allways set
_WIN32              is defined if the script is executed on the windows plattform
__MINGW32__         is defined if the script is executed on the Windows/Mingw plattform
__OS2__             is defined if the script is executed on the OS/2 plattform
__ZAURUS__          is defined if the script is executed on the ZAURUS plattform
__ANDROID__         is defined if the script is executed on the Android plattform
__APPLE__           is defined if the script is executed on an Apple/MacOS plattform
__linux__           is defined if the script is executed on the linux plattform
__UNKNOWN__         is defined if the script is executed on an unknown plattform
_NDEBUG             is defined if the script is executed without the --debug option
_DEBUG              is defined if the script is executed with the --debug option

Commandline options

Start minscript with the option -? for a complete list of available options.

Module interface

To generate a module see the demo module example.

The folowing steps are necessary

• write the C/C++ implementation of the module (example: module_test.h, module_test.cpp)
• generate the stub files for your implementation files using the minscript-program (example: minscript --mmakestubs >module_test.h.cpp)
• optional: if your implementation module uses classes, you have to generate wrapper-classes for the minscript interpreter: (example: minscript --makewrappers module_test.h >module_test.ic). Use this wrapper files with an #include statement.
• generate the makefile to create the shared library (linux) or dll (windows). (example: minscript --makemakefile module_test.h)
• generate the shared library (module.so) or dll (module.dll) with make or nmake.
• test the generated module (module.*) by loading the module with __loaddll("module.so") or __loaddll("module.dll")

All these steps are done in the script buildmodule.ic (minscript buildmodule.ic -a module_test.h).

License

Minscript is released under the GPL license

Warning: The minscript package comes without any warranty. Use it at your own risk.

Homepage: https://github.com/mneuroth/minscript