add README.

.gitignore

@@ -1,3 +1,4 @@
 /src/mpc/.git
 /src/mpc/.git/**
+/src/_mumble.c
 

README.md

@@ -0,0 +1,77 @@
+# Mumble: A lisp in C
+
+## About
+
+This is a Lisp written in C. It follows the outline in this [Build Your Own Lisp](https://buildyourownlisp.com/chapter11_variables) book, though it then adds some small tweaks and improvements and quality of life improvements:
+
+- A makefile
+- Configurable verbosity levels
+- Different and perhaps slightly more elegant printing functions
+- A slightly different approach to evaluating functions
+- Capturing Ctrl+D
+
+Overall this might be mostly of interest as a pointer to the book that this is originally based on. And to readers of that same book, I'd be curious to see what you ended up with.
+
+## Installation and usage
+
+### Dependencies
+
+This depends on [editline](https://github.com/troglobit/editline), which can be installed on Debian/Ubuntu with:
+
+```
+git clone https://github.com/troglobit/editline
+./autogen.sh
+./configure
+make all
+sudo make install
+ldconfig
+```
+
+Readers might also find it interesting to compile it with [tiny c compiler](https://bellard.org/tcc/) rather than gcc, as it is significantly faster.
+
+### Compilation
+
+```
+git clone https://github.com/NunoSempere/mumble
+make
+# sudo make install # 
+```
+
+### Usage
+
+Simply call the `./mumble` binary:
+
+```
+./mumble
+```
+
+## Example usage
+
+```
+mumble> (1 2 3)
+mumble> { 1 2 3 }
+mumble> head (1 2 3)
+mumble> { head (1 2 3) }
+mumble> tail { 1 2 3 }
+mumble> list ( 1 2 3 )
+mumble> eval { head {1 2 3} } 
+mumble> (eval { head {+ tail head } } ) 1 2 3 
+mumble> len {1 2 3}
+mumble> join { {1 2} {3 4} }
+mumble> def { {x} { 100 } }
+mumble> x
+mumble> def { { a b c } { 1 2 3} }
+mumble> * a b c
+mumble> - a b c
+mumble> / a b c
+mumble> VERBOSITY=0
+mumble> VERBOSITY=1
+mumble> VERBOSITY=2
+```
+
+
+## Gotchas
+
+This doesn't currently run on Windows. But it easily could, with [preprocessor statements from the book].
+
+

src/mumble.c

@@ -596,7 +596,7 @@ lispval* builtin_list(lispval* v, lispenv* e)
 
 lispval* builtin_len(lispval* v, lispenv* e)
 {
-    // tail { 1 2 3 }
+    // len { 1 2 3 }
     LISPVAL_ASSERT(v->count == 1, "Error: function len passed too many arguments");
 
     lispval* source = v->cell[0];
@@ -960,6 +960,7 @@ int main(int argc, char** argv)
         print_lispval_tree(env->vals[0], 2);
     if (VERBOSE)
         printfln("\n");
+
 		// Initialize a repl
     int loop = 1;
     while (loop) {
@@ -1007,11 +1008,12 @@ int main(int argc, char** argv)
                 }
                 delete_lispval(answer);
                 if (VERBOSE > 1)
-                    printfln("Answer after deletion: %p", answer);
+                    printfln("variable \"answer\" after deletion: %p", answer);
                 // delete_lispval(answer); // do this twice, just to see.
                 //if(VERBOSE) printfln("Deleting this lispval:");
                 // if(VERBOSE) print_lispval_tree(l,2);
-                delete_lispval(l);
+
+								// delete_lispval(l);
                 // if(VERBOSE) printfln("Deleted that ^ lispval");
                 // ^ I do not understand how the memory in l is freed.
                 // delete the ast