1. Description
-------------------
The module PASCALC.DCU is the Pascal-like language interpreter for Delphi.
The basic differences from standard Pascal the following:
- All variables stored as variants.
- It's no need to declare variables, labels and functions. PASCALC creates
variables dynamically on first assignment. Variable type depends on the
last value assigned, type checking is not carried out.
- Expressions syntax:
Arithmetic operators: +, -, *, /, ^ (power), SHL, SHL
Bitwise operators: BITOR,BITAND,BITXOR,BITNOT
Logical operators: >, <, >=, <=, =, <>, AND, OR, NOT,
constants TRUE and FALSE.
Operators precedence standard, you can use parentheses.
- Statements supported:
BEGIN... END
IF... THEN... ELSE
CASE
FOR... TO/DOWNTO... DO
WHILE... DO
REPEAT... UNTIL
BREAK
CONTINUE
GOTO
EXIT
USES
INCLUDE
- All reserved words are declared in interface section as string array.
You can change them to anyone others. All identifiers should be different
(except assignment and equation, they may be the same).
- Multi-dimensional arrays supported. Array items are variables whose names
consist from array name and indexes (in brackets). Array items properties
same as the simple variables. It's no need to declare arrays. Array index
continuity is not requred. It's possible to access string as char array.
You can assign chars or numbers in range 0..255 to string characters.
Array name should be unique, simple variable MyArr and array item MyArr[1]
can't exist at the same time. This rule allows to distinguish access to
1-st character of string variable MyArr (MyArr[1]) from the accees to
the first item of array MyArr. To access character of string array item,
character index should be written in brackets after item name, for example
MyArr[1,2][3].
- All build-in functions are user-defined. Module pasfunc.pas contain
example of PASCALC implementations for common Delphi functions. You can use
this functions and write your own implementations for necessary functions.
There is no need to declare parameters for user-defined functions, therefore
it's types and amount are not limited. If necessary you can provide type
checking inside function code. Interpreter calculates all parameter values
and creates temporary values list (TVarList). Names of var-parameters in this
list are 'VAR', otherwise 'VALUE'. After function call interpreter updates
values for var-parameters. Function result type not checked, one function can
return number as well as string. Functions can be called as procedures (without
result usage).
- Procedures and functions (in sense of the subroutines on interpreter language)
are supported. The function heading specifies only names of formal parameters,
without parameters types and pass method (var or value). Also, function's result
types are not declared. To return function result you should assign value to
variable "result".
If actual parameter is variable (not expression), it considered as var-parameter.
In this case assigning new value to this parameter inside procedure or function
will affect the actual parameter variable.
At the same time, all interpreter global variables inside a function or procedures
looks like local variables, with the same initial values as global ones.
You can change this values inside procedures (functions), but it's don't affect
the global variables. All new variables created inside procedures and functions
are local, and will be destroyed after exiting.
Therefore, it is possible to use any names for local variables, without conflicts
with the global variables.
For libraries implementation, it is possible to use operators USES and INCLUDE.
Syntax: USES 'filename';
INCLUDE 'filename';
INCLIDE and USES are parsed by pre-processor before script execution.
INCLUDE inserts text from file 'filename' into the script, USES loads
procedures and functions declarations.
2. License
----------
This software is provided as it is, without any kind of warranty given.
The author can not be held responsible for any kind of damage, problems etc,
arised from using this software. PASCALC interpreter is shareware product.
Unregistered version has no time or functionality limitations, but can
show info screen.
If you want get source code, you should register PASCALC and get registration code.
Use your registration code as password for source archive (Source\pascsrc.zip).
Address for online registration (price $20):
https://www.regnow.com/softsell/nph-softsell.cgi?item=2608-2
You can modify PASCALC source code as you need, distribute executable files
compiled with PASCALC source. But you can't distribute original or modified
PASCALC source code, .DCU units or libraries based on PASCALC source code.
3. PASCALC inteface
-------------------
unit pascalc;
{$F+,B-,R-}
interface
uses
Windows, Messages, SysUtils, Classes, Math;
type TToken =
(tEMPTY, tVR, tCON, tTRUE, tFALSE,
tEQU, tOR, tAND, tNOT, tXOR,
tCOMMA, tLBL, tNEQ, tGT, tLS,
tGTE, tLSE, tADD, tSUB, tMUL,
tDIV, tPWR, tLBR, tRBR, tLARR,
tRARR, tSEMI, tREM, tREMB, tREME,
tASSIGN, tBEGIN, tEND, tIF, tTHEN,
tELSE, tFOR, tTO, tDOWNTO, tDO,
tWHILE, tREPEAT, tUNTIL, tBREAK, tCONTINUE,
tEXIT, tGOTO, tSHL, tSHR, tPROC,
tFUNCT, tUSES, tINCLUDE, tCASE, tOF,
tCOMMA2);
type TTokenSet = set of TToken;
const
ResWords : array[TToken] of string[10] =
('', '', '', 'TRUE', 'FALSE',
'=', 'OR', 'AND', 'NOT', 'XOR',
',', ':', '<>', '>', '<',
'>=', '<=', '+', '-', '*',
'/', '^', '(', ')', '[',
']', ';', '//', '{', '}',
':=', 'BEGIN', 'END', 'IF', 'THEN',
'ELSE', 'FOR', 'TO', 'DOWNTO', 'DO',
'WHILE', 'REPEAT', 'UNTIL', 'BREAK', 'CONTINUE',
'EXIT', 'GOTO', 'SHL', 'SHR', 'PROCEDURE',
'FUNCTION', 'USES', 'INCLUDE', 'CASE', 'OF',
'..');
const
Alpha : set of char = ['_','0'..'9','a'..'z','A'..'Z','à'..'ÿ','¸','À'..'ß','¨'];
StrDelimiter : char = '''';
DecimalPoint : char = '.';
TokenDelimiter : char = #127;
type TVar = record
Name : string;
Value : variant;
end;
type TPVar = ^TVar;
type TVarList = class (TList)
destructor Destroy; override;
procedure ClearAll;
function AddVar(V:TVar) : boolean;
function AddValue(N:string; V:variant) : boolean;
function VarExist(N:string):boolean;
function VarIndex(N:string):integer;
function VarByName(N:string;var V:TVar) : boolean;
function SetVar(V:TVar) : boolean;
function SetValue(N:string; V:variant) : boolean;
procedure CopyTo(VL:TVarList);
end;
type TPVarList = ^TVarList;
type PProcessProc = procedure;
type PFunction = function(Sender:TObject; var A:TVarList; var R:TVar) : boolean;
type TFunc = record
Name : string;
Func : Pointer;
end;
type TPFunc = ^TFunc;
type TFuncList = class (TList)
destructor Destroy; override;
procedure ClearAll;
function AddFunction(N:string; F:Pointer) : boolean;
end;
type TProcedure = record
Name : string;
Body : string;
Params : string;
Result : boolean;
end;
type TPProcedure = ^TProcedure;
type TProcList = class(TList)
dest
评论0