Ok, here's my first attempt at using minipicolisp as a library. (Leaving aside
the issue of get/put for now. Basically replacing main() with:
#if !LIBRARY
/*** Main ***/
int main(int ac, char *av[]) {
char *p;
. . .
#else
// we're building as a library
void miniPicoLisp_init( const char * home_dir )
{
heapAlloc();
initSymbols();
if (home_dir) {
int l = strlen(home_dir) + 1;
Home = malloc( l );
memcpy(Home, home_dir, l );
Home[ l ] = '\0';
}
Reloc = Nil;
InFile = stdin, Env.get = getStdin;
OutFile = stdout, Env.put = putStdout;
// ??
ApplyArgs = cons(cons(consSym(Nil,0), Nil), Nil);
ApplyBody = cons(Nil,Nil);
}
any miniPicoLisp_dostring( char *str )
{
return load(NULL, 0, mkStr(str));
}
#endif
And then testing it with this:
#include "pico.h"
extern void miniPicoLisp_init( const char * home_dir );
extern any miniPicoLisp_dostring( char *str );
#define MAX_STR 1024
int main(int ac, char *av[]) {
char buf[MAX_STR];
miniPicoLisp_init( NULL );
while (fgets(buf, MAX_STR, stdin) != NULL) { // read
any v = miniPicoLisp_dostring( buf ); // eval
doPrint( v ); // print
}
return 0;
}
Doug
--- On Sat, 6/18/11, Alexander Burger <[email protected]> wrote:
> From: Alexander Burger <[email protected]>
> Subject: Re: embedding minipicolisp
> To: [email protected]
> Date: Saturday, June 18, 2011, 11:21 PM
> Hi Doug,
>
> > I'd like to embed minipicolisp in C applications I'd
> like to be able
> > to create a minipicolisp environment, and then pass
> strings to it
> > (commands) for execution. It would also be great to be
> able get back the
> > results in a string.
>
> The mechanism in PicoLisp to execute a string is 'load'. If
> an argument
> to 'load' starts with a hyphen, the rest is interpreted as
> an expression
> (without the surrounding parentheses). This mechanism is
> normally used
> to run expressions from the command line.
>
> The lower level functions for that are 'str', both for
> converting a
> transient symbol to a list (without the surrounding
> parentheses) and to
> do the reverse, and EVAL() (which is actually not a
> function but a
> macro).
>
> Unfortunately, there is no way currently to convert a C
> string directly
> to an executable Lisp expression (without the intermediate
> transient
> symbol).
>
>
> > In lua, you'd do something like,
> > L = lua_open();
>
> Here you'd need a function that initialized the PicoLisp
> VM, as is done
> by main(), i.e. calls heapAlloc(), initSymbol() etc.
>
>
> > luaL_dostring(L, str_in );
> > str_out = l_results_to_string(L);
>
> You need a C function similar to 'loadAll()'. It would call
> 'mkStr()' on
> the C string to create the transient symbol, then load() to
> run the
> expression.
>
> Better would be to cook something more specialized, similar
> to parse(),
> to avoid the intermediate transient symbol step.
>
>
> To pack the result into a C string, you need a mechanism
> similar to
> doStr().
>
> You define a function which writes a single byte into a C
> character
> array,
>
> void putCharC(int c) {
> *CBytePtr++ = c;
> }
>
> and store a pointer to that function into 'Env.put':
>
> void (*putSave)(int);
>
> putSave = Env.put;
> Env.put = putCharC;
> print(result);
> Env.put = putSave;
>
>
> Hope this helps.
>
> Cheers,
> - Alex
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