Rename possessive to structAccess.

Gives better error messages.
Use typical type-checking in structAccess.
Make checkTypes() more global, and move to pebblisp.c

src/env.c

@@ -422,7 +422,7 @@ struct Environment defaultEnv()
         pf(isErr),
         pf(charVal),
         pf(parseEvalO),
-        pf(possessive),
+        pf(structAccess),
         pf(getTime),
 #ifndef LOW_MEM
         pf(reverse),

src/object.c

@@ -580,6 +580,11 @@ inline int isBool(const Object test)
     return test.type == TYPE_BOOL;
 }
 
+inline int isStruct(const Object test)
+{
+    return test.type == TYPE_STRUCT;
+}
+
 inline int isFuncy(const Object test)
 {
     return test.type == TYPE_LAMBDA || test.type == TYPE_FUNC;

src/object.h

@@ -179,6 +179,8 @@ int isStringy(Object test);
 
 int isBool(Object test);
 
+int isStruct(Object test);
+
 int isFuncy(Object test);
 
 int isValidType(Object test);

src/pebblisp.c

@@ -314,23 +314,13 @@ Object eval(const Object* obj, struct Environment* env)
     return errorObject(BAD_TYPE);
 }
 
-Object possessive(Object* params, int length, struct Environment* env)
+Object structAccess(Object* params, int length, struct Environment* env)
 {
+    checkTypes(structAccess)
+
     Object structo = params[0];
     Object field = params[1];
 
-    if (structo.type != TYPE_STRUCT) {
-        printf("`'s` must be used on a struct!\n");
-        return errorObject(NULL_PARSE);
-    }
-    if (!isStringy(field)) {
-        printf("`'s` field name must be stringy! Received a ");
-        printType(&field);
-        printObj(&field);
-        printf("\n");
-        return errorObject(NULL_PARSE);
-    }
-
     struct StructDef* structDef = getStructAt(structo.structObject->definition);
     for (int i = 0; i < structDef->fieldCount; i++) {
         if (strcmp(field.string, structDef->names[i]) == 0) {
@@ -467,14 +457,14 @@ Result parseAtom(struct Slice* s)
     } else if (c == '"'/* || c == '\''*/) {
         return (Result) { objFromSlice(s->text, s->length), s };
     } else if (s->text[s->length] == '.') {
-        Object possessiveFunc = newObject(TYPE_FUNC);
-        possessiveFunc.func = &possessive;
-        Object list = startList(possessiveFunc);
-        Object possesser = symFromSlice(s->text, s->length);
-        nf_addToList(&list, possesser);
+        Object structAccessFunc = newObject(TYPE_FUNC);
+        structAccessFunc.func = &structAccess;
+        Object list = startList(structAccessFunc);
+        Object theStruct = symFromSlice(s->text, s->length);
+        nf_addToList(&list, theStruct);
         struct Slice* next = s + 2;
-        Object possessed = objFromSlice(&next->text[-1], next->length + 1);
-        nf_addToList(&list, possessed);
+        Object structField = objFromSlice(&next->text[-1], next->length + 1);
+        nf_addToList(&list, structField);
         return (Result) { list, next };
     }
     return (Result) { symFromSlice(s->text, s->length), s };
@@ -536,6 +526,22 @@ Object parseEval(const char* input, struct Environment* env)
     return obj;
 }
 
+Object typeCheck(const char* funcName, Object* params, int length,
+                 int (* typeChecks[])(Object), int typeLength, int* failed)
+{
+    *failed = 1;
+    if ((typeLength - 1) > length) {
+        return errorWithContext(NOT_ENOUGH_ARGUMENTS, funcName);
+    }
+    for (int i = 0; i < typeLength - 1; i++) {
+        if (typeChecks[i] && !typeChecks[i](params[i])) { // TODO: Use pl func name instead of C function name.
+            return /*errorObject(BAD_TYPE); */ errorWithContextLineNo(BAD_PARAMS_ON, funcName, 0, NULL);
+        }
+    }
+    *failed = 0;
+    return numberObject(0);
+}
+
 #ifdef STANDALONE
 
 int readFile(const char* filename, struct Environment* env)

src/pebblisp.h

@@ -64,6 +64,18 @@ Object listEvalLambda(Object* lambda, const Object* remaining, int evalLength,
 
 Object simpleFuncEval(Object func, Object arg1, Object arg2, struct Environment* env);
 
+Object typeCheck(const char* funcName, Object* params, int length,
+                 int (* typeChecks[])(Object), int typeLength, int* failed);
+
+#ifndef DISABLE_TYPE_CHECKS
+#define checkTypes(FUNC) int FAILED; Object ERROR = typeCheck(#FUNC, params, length, FUNC ## TypeChecks, array_length(FUNC ## TypeChecks), &FAILED); \
+if (FAILED) { \
+    return ERROR; \
+}
+#else
+#define checkTypes(FUNC) ;
+#endif
+
 #ifdef STANDALONE
 
 int _readFile(FILE* input, struct Environment* env);
@@ -82,4 +94,12 @@ fn(def, "def",
    "(def x 10) x", "10",
 );
 
+tfn(structAccess, "poss",
+    ({ isStruct, isStringy, NULL }),
+    "Get the value of a struct's field",
+    "(struct Post (title body))\n   "
+    "(def p (Post \"TI\" \"BO\"))\n   "
+    "p.title", "TI"
+);
+
 #endif

src/plfunc.c

@@ -3,31 +3,6 @@
 
 #include "plfunc.h"
 
-Object typeCheck(const char* funcName, Object* params, int length,
-                 int (* typeChecks[])(Object), int typeLength, int* failed)
-{
-    *failed = 1;
-    if ((typeLength - 1) > length) {
-        return errorWithContext(NOT_ENOUGH_ARGUMENTS, funcName);
-    }
-    for (int i = 0; i < typeLength - 1; i++) {
-        if (typeChecks[i] && !typeChecks[i](params[i])) { // TODO: Use pl func name instead of C function name.
-            return /*errorObject(BAD_TYPE); */ errorWithContextLineNo(BAD_PARAMS_ON, funcName, 0, NULL);
-        }
-    }
-    *failed = 0;
-    return numberObject(0);
-}
-
-#ifndef DISABLE_TYPE_CHECKS
-#define checkTypes(FUNC) int FAILED; Object ERROR = typeCheck(#FUNC, params, length, FUNC ## TypeChecks, array_length(FUNC ## TypeChecks), &FAILED); \
-if (FAILED) { \
-    return ERROR; \
-}
-#else
-#define checkTypes(FUNC) ;
-#endif
-
 Object reduce(Object* params, int length, struct Environment* env)
 {
     checkTypes(reduce)
@@ -377,7 +352,7 @@ Object numToChar(Object* params, int length, struct Environment* env)
     if (c.type != TYPE_NUMBER) {
         return errorObject(BAD_NUMBER);
     }
-    char ch[1] = {c.number};
+    char ch[1] = { c.number };
     return stringFromSlice(ch, 1);
 }
 

src/plfunc.h

@@ -189,14 +189,6 @@ fn(parseEvalO, "eval",
    "(eval '(+ 5 5))", "10",
 );
 
-/// STRUCT, STRING => ANY
-fn(possessive, "poss",
-   "Get the value of a struct's field",
-   "(struct Post (title body))\n   "
-   "(def p (Post \"TI\" \"BO\"))\n   "
-   "p.title", "TI"
-);
-
 #ifdef STANDALONE
 
 fn(print, "prn", "Prints the string representation of the given object to stdout.");