Tweak (eval) to accept SLIST arguments.

Tweak implicit-cat detection.
Explicit empty-string notation in test display.
A couple more tests.

src/env.c

@@ -251,7 +251,9 @@ struct helpText helpTexts[100];
 #define pf(_name, _func) buildFuncSym(_name, &(_func), _func ## Doc, _func ## Tests, array_length(_func ## Tests))
 
 int helpInitialized = 0;
-struct symFunc buildFuncSym(const char* symbol, Object (* func)(Object, Object, struct Environment*), const char* help, const char*const* tests, size_t testLength)
+
+struct symFunc buildFuncSym(const char* symbol, Object (* func)(Object, Object, struct Environment*), const char* help,
+                            const char* const* tests, size_t testLength)
 {
     if (!helpInitialized) {
         helpTexts[currentHelp].help = help;
@@ -295,7 +297,12 @@ char* getHelp(const char* symbol)
                     c++;
                 }
                 //textCursor += sprintf(textCursor, "\n  %s => %s", test, expected);
-                textCursor += sprintf(textCursor, " => %s", expected);
+                textCursor += sprintf(textCursor, " => ");
+                if (expected[0] == '\0') {
+                    textCursor += sprintf(textCursor, "<empty string>");
+                } else {
+                    textCursor += sprintf(textCursor, "%s", expected);
+                }
             }
             return text;
         }

src/object.c

@@ -907,6 +907,11 @@ inline int eitherIs(const enum Type type, const Object* o1, const Object* o2)
     return (o1->type == type) || (o2->type == type);
 }
 
+inline int eitherIsNot(const enum Type type, const Object* o1, const Object* o2)
+{
+    return (o1->type != type) || (o2->type != type);
+}
+
 inline int areSameType(const Object* obj1, const Object* obj2)
 {
     return obj1->type == obj2->type;

src/object.h

@@ -192,6 +192,8 @@ int isError(Object obj, enum errorCode err);
 
 int bothAre(enum Type type, const Object* obj1, const Object* obj2);
 
+int eitherIsNot(const enum Type type, const Object* o1, const Object* o2);
+
 int eitherIs(enum Type type, const Object* obj1, const Object* obj2);
 
 int areSameType(const Object* obj1, const Object* obj2);

src/pebblisp.c

@@ -1,7 +1,9 @@
 #ifdef STANDALONE
 #define _GNU_SOURCE
+
 #include <signal.h>
 #include <ucontext.h>
+
 #endif
 
 #include "pebblisp.h"
@@ -399,17 +401,12 @@ Object eval(const Object* obj, struct Environment* env)
         case TYPE_BOOL:
         case TYPE_STRING:
         case TYPE_STRUCT:
+        case TYPE_SLIST:
             return cloneObject(*obj);
 
         case TYPE_SYMBOL:
             return fetchFromEnvironment(obj->string, env);
 
-        case TYPE_SLIST: {
-            Object o = cloneObject(*obj);
-            o.type = TYPE_LIST;
-            return o;
-        }
-
         case TYPE_LIST:
             return evalList(obj, env);
 
@@ -480,7 +477,9 @@ Result parse(struct Slice* slices)
         struct Slice* rest = &slices[1];
         if (token->text[0] == '\'' && token->text[1] == '(') {
             Result r = readSeq(&slices[2]);
+            if (r.obj.type == TYPE_LIST) {
                 r.obj.type = TYPE_SLIST;
+            }
             return r;
         } else if (token->text[0] == '(') {
             // todo check for null rest
@@ -597,6 +596,7 @@ Result parseAtom(struct Slice* s)
 }
 
 struct Slice* lastOpen = NULL;
+
 Object parseEval(const char* input, struct Environment* env)
 {
     struct Error err = noError();
@@ -743,6 +743,7 @@ void loadArgsIntoEnv(int argc, const char* argv[], struct Environment* env)
 }
 
 int nestedSegfault = 0;
+
 void handler(int nSignum, siginfo_t* si, void* vcontext)
 {
     if (nestedSegfault) {

src/pebblisp.h

@@ -43,6 +43,8 @@ Result parseAtom(struct Slice* slice);
 
 Object parseEval(const char* input, struct Environment* env);
 
+Object evalList(const Object* obj, struct Environment* env);
+
 void evalForms(Object* destList, const Object* src, struct Environment* env);
 
 void copySlice(char* dest, struct Slice* src);

src/plfunc.c

@@ -86,6 +86,9 @@ Object rest(Object list, Object ignore, struct Environment* env)
 
 Object reverse(Object _list, Object ignore, struct Environment* ignore2)
 {
+    if (!isListy(_list)) {
+        return errorObject(NOT_A_LIST);
+    }
     const Object* list = &_list;
     Object rev = listObject();
 
@@ -137,6 +140,8 @@ Object parseEvalO(Object text, Object ignore, struct Environment* env)
         Object parsed = parseEval(string.string, env);
         cleanObject(&string);
         return parsed;
+    } else if (text.type == TYPE_SLIST) {
+        return evalList(&text, env);
     } else if (text.type != TYPE_STRING) {
         return errorObject(CAN_ONLY_EVAL_STRINGS);
     }
@@ -187,7 +192,7 @@ Object _basicOp(const Object* obj1, const Object* obj2, const char op,
 
     switch (op) {
         case '+':
-            if (eitherIs(TYPE_STRING, obj1, obj2)) {
+            if (eitherIsNot(TYPE_NUMBER, obj1, obj2)) {
                 return catObjects(*obj1, *obj2, env);
             }
             return numberObject(n1 + n2);

src/plfunc.h

@@ -30,29 +30,29 @@ BASIC_OP(or);
 
 fn(catObjects,
    "Concatenate string versions of the given objects.",
-  "(cat \"Stuff: \" (1 2 3))", "Stuff: ( 1 2 3 )"
+   "(cat \"Stuff: \" (1 2 3))", "Stuff: ( 1 2 3 )",
 )(Object obj1, Object obj2, struct Environment* env);
 
 fn(filter,
    "Filter a list based on the given condition.",
-  "(fil (< 50) (25 60 100))", "( 60 100 )"
+   "(fil (< 50) (25 60 100))", "( 60 100 )",
 )(Object condition, Object list, struct Environment* env);
 
 fn(append,
    "Append the given element. Creates a new list.",
-  "(ap (1 2) 3)", "( 1 2 3 )"
+   "(ap (1 2) 3)", "( 1 2 3 )",
 )(Object list, Object newElement, struct Environment* env);
 
 fn(prepend,
    "Prepend the given element. Creates a new list",
-  "(pre (2 3) 1)", "( 1 2 3 )"
+   "(pre (2 3) 1)", "( 1 2 3 )",
 )(Object list, Object newElement, struct Environment* env);
 
 fn(len,
    "Returns the length of the given list, or a NOT_A_LIST error if the expression is not a list.",
    "(len (2 3))", "2",
    "(len ())", "0",
-  "(len \"string\")", "NOT_A_LIST"
+   "(len \"string\")", "NOT_A_LIST",
 )(Object obj1, Object o_ignore, struct Environment* e_ignore);
 
 fn(reduce,
@@ -61,20 +61,36 @@ fn(reduce,
    " - A two-element list: (`values` `initial`)\n"
    " - A function to apply to each value.",
    "(reduce (5 6) +)", "11",
-  "(reduce ((1 2 3) 0) +)", "6"
+   "(reduce ((1 2 3) 0) +)", "6",
 )(Object listInitial, Object func, struct Environment* env);
 
-fn(at, "(at 1 (1 2 3)) => 2")
+fn(at,
-(Object index, Object list, struct Environment* env);
+   "Get item at the given index in the given list.",
+   "(at 1 (1 2 3))", "2",
+   "(at 99 (1 2 3))", "INDEX_PAST_END",
+   "(at 99 \"string\")", "INDEX_PAST_END",
+)(Object index, Object list, struct Environment* env);
 
-fn(rest, "(rest (1 2 3)) => ( 2 3 )")
+fn(rest,
-(Object list, Object ignore, struct Environment* env);
+   "Get the tail of a list. All but the first element.",
+   "(rest (1 2 3))", "( 2 3 )",
+   "(rest ())", "( )",
+   "(rest \"string\")", "( )",
+)(Object list, Object ignore, struct Environment* env);
 
-fn(reverse, "(rev (1 2 3)) => ( 3 2 1 )")
+fn(reverse,
-(Object _list, Object ignore, struct Environment* ignore2);
+   "Reverse a list.",
+   "(rev (1 2 3))", "( 3 2 1 )",
+   "(rev \"string\")", "NOT_A_LIST",
+)(Object _list, Object ignore, struct Environment* ignore2);
 
-fn(isNum, "(isnum 1) => T\n(isnum \"Hello\") => F")
+fn(isNum,
-(Object test, Object ignore, struct Environment* ignore2);
+   "Returns `T` only if the argument evaluates to a number.",
+   "(isnum 1)", "T",
+   "(isnum (+ 5 5))", "T",
+   "(isnum '(+ 5 5))", "F",
+   "(isnum \"Hello\")", "F",
+)(Object test, Object ignore, struct Environment* ignore2);
 
 fn(isList,
    "Returns `T` only if the argument is a list.",
@@ -84,29 +100,37 @@ fn(isList,
 )(Object test, Object ignore, struct Environment* ignore2);
 
 fn(isString,
-  "(isstr \"Heyo\") => T\n"
+   "Returns `T` only if the argument is a string.",
-  "(isstr \"\") => T\n"
+   "(isstr \"Heyo\")", "T",
-  "(isstr 10) => F"
+   "(isstr \"\")", "T",
+   "(isstr (cat 5 5))", "T",
+   "(isstr 10)", "F",
 )(Object test, Object ignore, struct Environment* ignore2);
 
 fn(isErr,
-   "(iserr (eval \"(((\") => T\n"
+   "Check if the argument is an error.",
-   "(iserr 5) => F"
+   "(iserr (at 10 ()))", "T",
+   "(iserr 5)", "F",
 )(Object test, Object ignore, struct Environment* ignore2);
 
 fn(charAt,
-  "(chat \"Hello\" 1) => \"e\"\n"
+   "Get the char in the given string at the given index.",
-  "(chat \"Hello\" 10) => \"\""
+   "(chat \"Hello\" 1)", "e",
+   "(chat \"Hello\" 10)", "",
 )(Object string, Object at, struct Environment* ignore);
 
 fn(charVal,
-  "(char \"h\") => 104\n"
+   "Get the ascii integer representaton of the given character.",
-  "(char \"hello\") => 104\n"
+   "(char \"h\")", "104",
-  "(char \"\") => 0"
+   "(char \"hello\")", "104",
+   "(char \"\")", "0",
 )(Object test, Object ignore, struct Environment* ignore2);
 
-fn(parseEvalO, "(eval \"(1 2 3)\") => (1 2 3)")
+fn(parseEvalO,
-(Object text, Object ignore, struct Environment* env);
+   "Evaluate the given string or quoted list.",
+   "(eval \"(1 2 3)\")", "( 1 2 3 )",
+   "(eval '(+ 5 5))", "10",
+)(Object text, Object ignore, struct Environment* env);
 
 fn(possessive,
    "(struct Post (title body))\n"