// ===============================================================================================================================
// allen_interpreter.h - Allen Programming Language - Sat Dec 22.
// ===============================================================================================================================
// Copyright (c) 2007, Soleil, BSD License.
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of the Garabatos de licor nor the names of its contributors may
// be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// This software is provided by the copyright holders and contributors
// "as is" and any express or implied warranties, including, but not
// limited to, the implied warranties of merchantability and fitness for
// a particular purpose are disclaimed. in no event shall the copyright owner or
// contributors be liable for any direct, indirect, incidental, special,
// exemplary, or consequential damages (including, but not limited to,
// procurement of substitute goods or services; loss of use, data, or
// profits; or business interruption) however caused and on any theory of
// liability, whether in contract, strict liability, or tort (including
// negligence or otherwise) arising in any way out of the use of this
// software, even if advised of the possibility of such damage.
// ===============================================================================================================================
// Allen virtual machine.
// ===============================================================================================================================
// AllenVM is fairly simple. The virtual machine model is handled by different states
// that define what or how it behaves while running the current program. So far those
// states allow feedback of userlevel functions and actions and provide ways to
// extend the states accordingly.
// VM States.
enum {
AllenVM_BREAK, // Stop execution.
AllenVM_CONTINUE, // Continue execution.
AllenVM_ERROR, // Error detected.
AllenVM_SUCCESS, // Everything ok.
AllenVM_RETURN, // Return value.
};
// ===============================================================================================================================
// Allen virtual machine errors.
// ===============================================================================================================================
// Sometimes during execution, Allen programs throw errors or exceptions to the user.
// As far as the VM goes, programs should never segfault, so safety is ensured and
// any error causes program termination.
#define VM_ERROR_FUNC_FOUND "Error: Function:'%s' already defined."
#define VM_ERROR_FUNC_NOTFOUND "Error: Function:'%s' undefined in current scope."
#define VM_ERROR_SVAR_NOTFOUND "Error: Single: '%s' undefined in current scope."
// ===============================================================================================================================
// Allen internal structures.
// ===============================================================================================================================
// AllenVM is structured in a very simple (but efective) way. All functions, single
// variables, objects and instances are handled by linked lists, beeing easily
// identified and accesible through program execution.
// There is no compilation stage, nor bytecode translation or code generation.
// Everything is executed on the fly using function pointers. This also allows
// for more dynamic implementations and code traversing. Higher order functions,
// functional programming and other tasks.
// Allen interpreter.
// As you can run different interpreters at the same time, this is the main
// structure defining the interpreter itself.
struct AllenVM_Interpreter {
int i_Ident; // Interpreter identifier.
int i_Level; // Current level of execution.
char* c_result; // Last function result.
struct AllenVM_Function *st_Function; // Local functions.
struct AllenVM_Scope *st_Scope; // Interpreter scope.
};
// Allen single variable.
// Single vars, wether integers, strings, characters, objects or macros are
// all handled by the same linked list. We store the name and the value
// and link it to the next single variable.
struct AllenVM_Single {
char *c_Name; // Variable name.
char *c_Value; // Variable value.
struct AllenVM_Single *st_Next; // Link to the next single var in the list.
};
// Allen native C calls.
// Every Allen standard function is mapped to a C native function, so you can
// extend the interpreter using C itself as well as using Allen itself.
typedef int (*AllenVM_NativeCall) (struct AllenVM_Interpreter *i, int argc, char **argv, void *data);
// Allen Function.
// Every single sentence in Allen programs is a function. And every single
// sentence returns a value. So we need to store functions and be able to traverse
// them looking for the native C call that they execute. We handle user-defined functions
// by asigning private data to this structure, but that is clearer in the function library.
struct AllenVM_Function {
char *c_Name; // Function name.
void *v_Data; // Private data used by the function.
AllenVM_NativeCall Function; // Native C call that this function may use.
struct AllenVM_Function *st_Next; // Link to the next function in the list.
};
// Allen Scopes.
// Scopes are the way we define global and local variables in our programs.
// Each scope defines two structures. One stores all the variables in our current
// scope, while the other is just a handler to be able to return to the parent
// scope after a function call.
struct AllenVM_Scope {
struct AllenVM_Single *st_Single; // Single variables in this scope.
struct AllenVM_Scope *st_Parent; // Parent scope that called this one.
};
// ===============================================================================================================================
// EOF
// ===============================================================================================================================
// Compiling this file: Gcc -O2 -lm
// Recommended code editor: Scite/Gedit/Vim.