More JSON-y struct string representation

Reviewed-on: #1

README.md

@@ -1,4 +1,4 @@
-# PebbLisp
+# ![PebbLisp](https://git.sagev.space/sage/pebblisp/raw/branch/master/resources/images/pebblisp-logo-white.png)
 
 A very basic LISP implementation with an interpreter and editor written for the Pebble.
 
@@ -90,15 +90,14 @@ write:
 
 Calling it is as simple as `(sq 5)`, which returns `25`.
 
-Lambdas can also be applied anonymously, as in `((fn (a) (* a a)) 5)`, which also returns `25`.
-This is most useful when using something like `map`. For example, an anonymous lambda could be used to square each
+Lambdas can also be applied anonymously. This is most useful when using something like `map`. For example, an anonymous lambda could be used to square each
 element in a list:
 
 ```
 (map (fn (a) (* a a)) (1 2 3 5 8 13 21 34))
 ```
 
-This is particularly useful on a low-memory device like the Pebble, where it may be useful to avoid storing the named
+This is particularly valuable on a low-memory device like the Pebble, where it may be wise to avoid storing the named
 lambda object in the environment.
 
 Lambdas may also have no arguments:
@@ -147,19 +146,19 @@ input list.
 
 ## Fil
 
-`fil` returns a filtered list, based on a given list and a given condition. Partial function support in PebbLisp is
-nowhere near comprehensive, but `fil` operates on the bare notion that currently exists. The general form of a `fil`
+`fil` returns a filtered list, based on a given list and a given condition. The general form of a `fil`
 expression is
 
 ```
-(fil (partial-condition) (candidate-list))
+(fil (condition) (candidate-list))
 ```
 
-Each element in the candidate list is compared against the partial condition. If the comparison returns true, it is
-added to the returned list. For example:
+Each element in the candidate list is compared against the
+condition. If the comparison returns true, it is added to the
+returned list. For example:
 
 ```
-(fil (< 100) (20 150 30 200))
+(fil (fn (a) (> a 100)) (20 150 30 200))
 ```
 
 would return `( 150 200 )`, as no other elements fit the condition `(< 100 n)`.

src/object.c

@@ -191,7 +191,12 @@ void stringStruct(struct string* s, const Object* obj)
 
     struct StructDef* def = getStructAt(so->definition);
     for (int i = 0; i < def->fieldCount; i++) {
-        appendf(s, " %s: ", def->names[i]);
+        appendf(s, " \"%s\": ", def->names[i]);
+        if (so->fields[i].type == TYPE_SYMBOL && so->fields[i].string == NULL) {
+            appendf(s, "null,");
+            continue;
+        }
+
         int isString = so->fields[i].type == TYPE_STRING;
         if (isString) {
             appendf(s, "\"");

src/tests.sh

@@ -206,7 +206,7 @@ title "Structs"
 check "Struct Definition" "(struct Post (title body))" "T"
 check "Building a struct"\
     '(struct Post (title body)) (Post "A title" "The Body")'\
-    '{ title: "A title", body: "The Body" }'
+    '{ "title": "A title", "body": "The Body" }'
 check "Accessing struct fields"\
     "(struct Post (title body)) (def p (Post \"TITLE\" \"BODY\")) (p.title p.body)"\
     "( TITLE BODY )"