lexer.c


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#include <u.h>
#include <libc.h>
#include <bio.h>

#include "apl9.h"

Rune primmonopnames[] = L"¨⍨⌸⌶&";
Rune primdyadopnames[] = L"⍣.∘⍤⍥@⍠⌺";
Rune primhybridnames[] = L"/\⌿⍀";

Datum *
lexline(Rune *line, int *ntoks, Symtab *symtab)
{
	int offset = 0;
	int len = runestrlen(line);
	Datum *tokens = mallocz(sizeof(Datum) * MAX_LINE_TOKENS, 1);
	*ntoks = 0;
	while(offset < len){
		Rune *p;
		if(isspacerune(line[offset])){
			offset++;
			continue;
		}else if(runestrchr(L"(){}[]←", line[offset])){
			switch(line[offset]){
			case '(': tokens[*ntoks].tag = LParTag; break;
			case ')': tokens[*ntoks].tag = RParTag; break;
			case '{': tokens[*ntoks].tag = LCurlTag; break;
			case '}': tokens[*ntoks].tag = RCurlTag; break;
			case '[': tokens[*ntoks].tag = LBracketTag; break;
			case ']': tokens[*ntoks].tag = RBracketTag; break;
			case L'←': tokens[*ntoks].tag = ArrowTag; break;
			}
			offset++;
		}else if(p = runestrchr(primfuncnames, line[offset])){
			tokens[*ntoks].tag = FunctionTag;
			tokens[*ntoks].func.code = p-primfuncnames;
			offset++;
		}else if(p = runestrchr(primmonopnames, line[offset])){
			tokens[*ntoks].tag = MonadicOpTag;
			tokens[*ntoks].func.code = p-primmonopnames;
			offset++;
		}else if(p = runestrchr(primdyadopnames, line[offset])){
			tokens[*ntoks].tag = DyadicOpTag;
			tokens[*ntoks].func.code = p-primdyadopnames;
			offset++;
		}else if(isdigitrune(line[offset])){
			char buf[64];
			char *p = buf;
			while(isdigitrune(line[offset])){
				p += runetochar(p, &line[offset]);
				offset++;
			}
			*p = 0;
			tokens[*ntoks].tag = ArrayTag;
			tokens[*ntoks].array = mkscalarint(atoll(buf));
		}else if(isalpharune(line[offset])){
			Rune buf[64];
			Rune *p = buf;
			while(isalpharune(line[offset])){
				*p = line[offset];
				p++;
				offset++;
			}
			*p = 0;
			tokens[*ntoks].tag = NameTag;
			tokens[*ntoks].symbol = getsym(symtab, buf);
		}else{
			print("Can't lex: %S\n", &line[offset]);
			*ntoks = 0;
			break;
		}
		(*ntoks)++;
	}
	return tokens;
}