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#include <u.h>
#include <libc.h>
#include <bio.h>
#include "apl9.h"
Rune *errormsg;
typedef Datum (*evalfn)(Datum, Datum);
Datum strand(Datum, Datum);
Datum monadfun(Datum, Datum);
Datum dyadfun(Datum, Datum);
Datum lpar(Datum, Datum);
Datum rpar(Datum, Datum);
int bindingstrengths[12][12] = {
/* A F H MO DO AF ( ) { } [ ] */
3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* A */
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* F */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* H */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* MO */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* DO */
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* AF */
4, 4, 4, 4, 4, 4, 0, 5, 4, 4, 4, 4, /* ( */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ) */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* { */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* } */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* [ */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ] */
};
evalfn evalfns[12][12] = {
/* A F H MO DO AF ( ) { } [ ] */
strand, dyadfun, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* A */
monadfun, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* F */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* H */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* MO */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* DO */
monadfun, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* AF */
lpar, lpar, lpar, lpar, lpar, 0, lpar, rpar, lpar, lpar, lpar, lpar, /* ( */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ) */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* { */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* } */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* [ */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* ] */
};
Datum *
eval(Datum *tokens, int *ntoks)
{
while(*ntoks > 1){
int maxlevel = 0;
int offset;
evalfn fn = nil;
print("CURRENT: %S\n", ppdatums(tokens, *ntoks));
for(offset = (*ntoks)-1; offset >= 0; offset--){
int level;
if(offset == 0)
level = 0;
else{
Datum left = tokens[offset-1];
Datum right = tokens[offset];
level = bindingstrengths[left.tag][right.tag];
}
if(level < maxlevel){
Datum left = tokens[offset];
Datum right = tokens[offset+1];
fn = evalfns[left.tag][right.tag];
print("Reducing %S and %S\n", ppdatum(left), ppdatum(right));
break;
}else if(level > maxlevel)
maxlevel = level;
}
if(maxlevel == 0){
errormsg = L"No reduce rule. Syntax error.";
*ntoks = 0;
}else{
tokens[offset] = fn(tokens[offset],tokens[offset+1]);
for(int i = offset+1; i < (*ntoks)-1; i++)
tokens[i] = tokens[i+1];
(*ntoks)--;
}
}
return tokens;
}
Datum
strand(Datum left, Datum right)
{
print("Stranding\n");
Datum result;
Array *leftarr = left.array->stranded ? left.array : fnEnclose(left.array);
Array *rightarr = right.array->stranded ? right.array : fnEnclose(right.array);
result.tag = ArrayTag;
result.array = fnCatenateFirst(leftarr, rightarr);
result.array->stranded = 1;
return result;
}
Datum
monadfun(Datum left, Datum right)
{
print("Monadic function application\n");
Datum result;
result.tag = ArrayTag;
/* TODO handle undefined functions here */
if(left.func.left)
result.array = dyadfunctiondefs[left.code](left.func.left, right.array);
else
result.array = monadfunctiondefs[left.code](right.array);
return result;
}
Datum
dyadfun(Datum left, Datum right)
{
print("Applying left argument to function\n");
Datum result;
result.tag = BoundFunctionTag,
result.func = right.func;
result.func.left = left.array;
return result;
}
Datum
lpar(Datum left, Datum right)
{
/* build up a parthenthesised expression */
left.expr.ntoks++;
left.expr.toks = realloc(left.expr.toks, sizeof(Datum) * left.expr.ntoks);
left.expr.toks[left.expr.ntoks-1] = right;
print("LPAR: %S\n", ppdatums(left.expr.toks, left.expr.ntoks));
return left;
}
Datum
rpar(Datum left, Datum right)
{
/* evaluate a parenthesis expression and return the result */
USED(right);
print("RPAR: %S\n", ppdatums(left.expr.toks, left.expr.ntoks));
Datum *result = eval(left.expr.toks, &left.expr.ntoks);
result[0].array->stranded = 0;
return result[0]; /* TODO handle error if ntoks != 1 */
}
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