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"/\⌿⍀";

Statement *
lexline(Rune *line)
{
	int offset = 0;
	int len = runestrlen(line);
	Statement *stmt = malloc(sizeof(Statement));
	stmt->ntoks = 0;
	stmt->toks = mallocz(sizeof(Datum) * MAX_LINE_TOKENS, 1);
	stmt->next = nil;

	while(offset < len){
		Rune *p;
		if(isspacerune(line[offset])){
			offset++;
			continue;
		}else if(runestrchr(L"()[]←⋄⍝", line[offset])){
			switch(line[offset]){
			case '(': stmt->toks[stmt->ntoks].tag = LParTag; break;
			case ')': stmt->toks[stmt->ntoks].tag = RParTag; break;
			case '[': stmt->toks[stmt->ntoks].tag = LBracketTag; break;
			case ']': stmt->toks[stmt->ntoks].tag = RBracketTag; break;
			case L'←': stmt->toks[stmt->ntoks].tag = ArrowTag; break;
			case L'⋄': stmt->next = lexline(&line[offset+1]); goto end;
			case L'⍝': goto end;
			}
			offset++;
		}else if(line[offset] == L'{'){
			Rune buf[MAX_LINE_LENGTH];
			Rune *p = buf;
			offset++;
			while(line[offset] != L'}' && offset < len){
				*p = line[offset];
				p++;
				offset++;
			}
			if(line[offset] != L'}')
				goto syntax_error;
			*p = 0;
			offset++;
			stmt->toks[stmt->ntoks].tag = FunctionTag;
			stmt->toks[stmt->ntoks].func.type = FunctypeDfn;
			stmt->toks[stmt->ntoks].func.dfn = runestrdup(buf);
		}else if(p = runestrchr(primfuncnames, line[offset])){
			stmt->toks[stmt->ntoks].tag = FunctionTag;
			stmt->toks[stmt->ntoks].func.type = FunctypePrim;
			stmt->toks[stmt->ntoks].func.code = p-primfuncnames;
			offset++;
		}else if(p = runestrchr(primmonopnames, line[offset])){
			stmt->toks[stmt->ntoks].tag = MonadicOpTag;
			stmt->toks[stmt->ntoks].func.code = p-primmonopnames;
			offset++;
		}else if(p = runestrchr(primdyadopnames, line[offset])){
			stmt->toks[stmt->ntoks].tag = DyadicOpTag;
			stmt->toks[stmt->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;
			stmt->toks[stmt->ntoks].tag = ArrayTag;
			stmt->toks[stmt->ntoks].array = mkscalarint(atoll(buf));
		}else if(runestrchr(L"⍺⍵", line[offset])){
			Rune *name = L"?";
			name[0] = line[offset];
			stmt->toks[stmt->ntoks].tag = NameTag;
			stmt->toks[stmt->ntoks].symbol = getsym(currentsymtab, name);
			offset++;
		}else if(isalpharune(line[offset]) || line[offset] == L'⎕'){
			int quadname = L'⎕' == line[offset];
			Rune buf[64];
			Rune *p = buf;
			while(isalpharune(line[offset]) || (line[offset] == L'⎕' && p == buf)){
				if(quadname)
					*p = toupperrune(line[offset]);
				else
					*p = line[offset];
				p++;
				offset++;
			}
			*p = 0;
			stmt->toks[stmt->ntoks].tag = NameTag;
			stmt->toks[stmt->ntoks].symbol = getsym(currentsymtab, buf);
		}else{
syntax_error:
			print("Can't lex: %S\n", &line[offset]);
			free(stmt->toks);
			free(stmt);
			return 0;
		}
		stmt->ntoks++;
	}
end:
	stmt->toks = realloc(stmt->toks, sizeof(Datum) * stmt->ntoks);
	return stmt;
}