Add apfl_string_eq macro

It's easy to forget the `== 0` after the apfl_string_cmp() call, so let's
add a macro that does the job for us.

src/apfl.h

@@ -48,6 +48,7 @@ struct apfl_string_view apfl_string_view_from_string(struct apfl_string);
 int apfl_string_view_cmp(struct apfl_string_view, struct apfl_string_view);
 
 #define apfl_string_cmp(a, b) apfl_string_view_cmp(apfl_string_view_from(a), apfl_string_view_from(b))
+#define apfl_string_eq(a, b) (apfl_string_cmp((a), (b)) == 0)
 
 void apfl_string_deinit(struct apfl_string *);
 bool apfl_string_copy(struct apfl_string *dst, struct apfl_string_view src);

src/expr.c

@@ -801,7 +801,7 @@ const_eq(struct apfl_expr_const a, struct apfl_expr_const b)
     case APFL_EXPR_CONST_BOOLEAN:
         return a.boolean == b.boolean;
     case APFL_EXPR_CONST_STRING:
-        return apfl_string_cmp(a.string, b.string) == 0;
+        return apfl_string_eq(a.string, b.string);
     case APFL_EXPR_CONST_NUMBER:
         return a.number == b.number;
     }
@@ -819,7 +819,7 @@ param_eq(struct apfl_expr_param a, struct apfl_expr_param b)
 
     switch (a.type) {
     case APFL_EXPR_PARAM_VAR:
-        return apfl_string_cmp(a.var, b.var) == 0;
+        return apfl_string_eq(a.var, b.var);
     case APFL_EXPR_PARAM_CONSTANT:
         return const_eq(a.constant, b.constant);
     case APFL_EXPR_PARAM_PREDICATE:
@@ -844,7 +844,7 @@ assignable_eq(struct apfl_expr_assignable a, struct apfl_expr_assignable b)
 
     switch (a.type) {
     case APFL_EXPR_ASSIGNABLE_VAR:
-        return apfl_string_cmp(a.var, b.var) == 0;
+        return apfl_string_eq(a.var, b.var);
     case APFL_EXPR_ASSIGNABLE_CONSTANT:
         return const_eq(a.constant, b.constant);
     case APFL_EXPR_ASSIGNABLE_PREDICATE:
@@ -854,7 +854,7 @@ assignable_eq(struct apfl_expr_assignable a, struct apfl_expr_assignable b)
         return assignable_eq(*a.expand, *b.expand);
     case APFL_EXPR_ASSIGNABLE_DOT:
         return assignable_eq(*a.dot.lhs, *b.dot.lhs)
-            && apfl_string_cmp(a.dot.rhs, b.dot.rhs) == 0;
+            && apfl_string_eq(a.dot.rhs, b.dot.rhs);
     case APFL_EXPR_ASSIGNABLE_AT:
         return assignable_eq(*a.at.lhs, *b.at.lhs)
             && apfl_expr_eq(*a.at.rhs, *b.at.rhs);
@@ -925,14 +925,14 @@ apfl_expr_eq(struct apfl_expr a, struct apfl_expr b)
             && apfl_expr_eq(*a.assignment.rhs, *b.assignment.rhs);
     case APFL_EXPR_DOT:
         return apfl_expr_eq(*a.dot.lhs, *b.dot.lhs)
-            && apfl_string_cmp(a.dot.rhs, b.dot.rhs) == 0;
+            && apfl_string_eq(a.dot.rhs, b.dot.rhs);
     case APFL_EXPR_AT:
         return apfl_expr_eq(*a.at.lhs, *b.at.lhs)
             && apfl_expr_eq(*a.at.rhs, *b.at.rhs);
     case APFL_EXPR_CONSTANT:
         return const_eq(a.constant, b.constant);
     case APFL_EXPR_VAR:
-        return apfl_string_cmp(a.var, b.var) == 0;
+        return apfl_string_eq(a.var, b.var);
     }
 
     assert(false);

src/parser.c

@@ -1820,18 +1820,18 @@ parse_fragment(apfl_parser_ptr p, struct fragment *fragment, bool need, enum par
         fragment->position = p->token.position;
         break;
     case APFL_TOK_NAME:
-        if (apfl_string_cmp(p->token.text, "nil") == 0) {
+        if (apfl_string_eq(p->token.text, "nil")) {
             fragment->type = FRAG_CONSTANT;
             fragment->constant = (struct apfl_expr_const) {
                 .type = APFL_EXPR_CONST_NIL,
             };
-        } else if (apfl_string_cmp(p->token.text, "true") == 0) {
+        } else if (apfl_string_eq(p->token.text, "true")) {
             fragment->type = FRAG_CONSTANT;
             fragment->constant = (struct apfl_expr_const) {
                 .type = APFL_EXPR_CONST_BOOLEAN,
                 .boolean = true,
             };
-        } else if (apfl_string_cmp(p->token.text, "false") == 0) {
+        } else if (apfl_string_eq(p->token.text, "false")) {
             fragment->type = FRAG_CONSTANT;
             fragment->constant = (struct apfl_expr_const) {
                 .type = APFL_EXPR_CONST_BOOLEAN,

src/tokenizer_test.c

@@ -109,7 +109,7 @@ expect_text_token(struct tokenizer_test *tt, int line, int col, enum apfl_token_
 {
     struct apfl_token tok;
     if (expect_token(tt, line, col, type, &tok)) {
-        if (apfl_string_cmp(text, tok.text) != 0) {
+        if (!apfl_string_eq(text, tok.text)) {
             test_failf(tt->t, "Token has wrong content. have=\"" APFL_STR_FMT "\", want=\"%s\"", APFL_STR_FMT_ARGS(tok.text), text);
         }
         apfl_token_deinit(&tok);