PS: fix function closures. Self-hosted up to step7.

15 files changed, 236 insertions, 184 deletions

diff --git a/ps/core.ps b/ps/core.ps
index afda426..590388a 100644
--- a/ps/core.ps
+++ b/ps/core.ps
@@ -40,12 +40,17 @@ end } def
 
 % [hashmap key] -> hash_map_get -> value
 /hash_map_get {
-    dup 0 _nth /data get % stack: args dict
-    exch 1 _nth % stack: dict key
-    2 copy known { %if has key
-        get
-    }{
+    dup 0 _nth % stack: args hash_map
+    dup null eq { %if hash_map is a nil
         pop pop null
+    }{ %else hash_map is not a nil
+        /data get % stack: args dict
+        exch 1 _nth % stack: dict key
+        2 copy known { %if has key
+            get
+        }{
+            pop pop null
+        } ifelse
     } ifelse
 } def
 
@@ -172,7 +177,12 @@ end } def
 
 % [obj] -> meta -> meta
 /meta {
-    0 _nth dup /meta known { /meta get }{ null } ifelse
+    0 _nth % stack: obj
+    dup type /dicttype eq { %if dictionary
+        dup /meta known { /meta get }{ null } ifelse
+    }{ %else
+        pop null % no meta on non-collections
+    } ifelse
 } def
 
 
@@ -196,7 +206,7 @@ end } def
     [ atm /data get ] 
     args 2 args _count 2 sub _slice /data get
     concatenate _list_from_array
-    args 1 _nth callable % make sure function is callable
+    args 1 _nth callable % extract proc
     exec
     /new_val exch def
     atm /data new_val put
diff --git a/ps/env.ps b/ps/env.ps
index b8752af..4eb3484 100644
--- a/ps/env.ps
+++ b/ps/env.ps
@@ -22,6 +22,8 @@
     >>
 end } def
 
+% env key -> env_find -> env
+% env key -> env_find -> null
 /env_find { 2 dict begin
     /key exch def
     /env exch def
@@ -34,27 +36,24 @@ end } def
     } ifelse } ifelse
 end } def
 
-/env_set { 4 dict begin
-    dup
-    /func? exch xcheck def % executable function
-    /val exch cvlit def
-    /key exch def
-    /env exch def
-    env key val func? { cvx } if put
-    val func? { cvx } if
-end } def
+% env key val -> env_set -> val
+/env_set {
+    dup 4 1 roll % stack: val env key val
+    put % stack: val
+} def
 
-/env_get { 2 dict begin
-    /key exch def
-    /env exch def
-    env key env_find
+/env_get {
+    dup 3 1 roll % stack: key env key
+    env_find % stack: key env/null
     dup null eq {
-        (')
-        key dup length string cvs
+        pop % stack: key
+        (') exch % stack: (') key
+        dup length string cvs
         (' not found)
         concatenate concatenate
         _throw
     }{
-        key get
+        exch % stack: env key
+        get
     } ifelse
-end } def
+} def
diff --git a/ps/printer.ps b/ps/printer.ps
index 1be0963..de91d80 100644
--- a/ps/printer.ps
+++ b/ps/printer.ps
@@ -5,9 +5,8 @@
 % ast print_readably -> _pr_str -> string
 /_pr_str { 4 dict begin
     /print_readably exch def
-    dup
-    /func? exch xcheck def % executable function
-    /obj exch cvlit def
+    dup xcheck { (Cannot print proc: ) print dup == quit } if % assert
+    /obj exch def
     obj _sequential? {
         obj _list? { (\() (\)) }{ ([) (]) } ifelse
         obj /data get ( ) print_readably _pr_str_args
@@ -19,7 +18,13 @@
         ( ) print_readably _pr_str_args
         concatenate
         (}) concatenate
-    }{ obj _mal_function? { % if user defined function
+    }{ obj _function? { % if builtin function
+        (<\(builtin_fn* {)
+        obj /data get dup length array copy cvlit
+        ( ) print_readably _pr_str_args
+        (}>)
+        concatenate concatenate
+    }{ obj _mal_function? { % if user defined mal_function
         (<\(fn* )
         obj /params get print_readably _pr_str
         ( )
@@ -33,10 +38,10 @@
         concatenate concatenate
     }{ /arraytype obj type eq { % if list or code block
         % accumulate an array of strings
-        func? { (<builtin_fn* { ) }{ (\() } ifelse
+        (\()
         obj ( ) print_readably _pr_str_args
         concatenate
-        func? { ( } >) }{ (\)) } ifelse
+        (\))
         concatenate
     }{ /integertype obj type eq { % if number
         /slen obj 10 add log ceiling cvi def
@@ -60,7 +65,7 @@
         obj dup length string cvs
     }{
         (<unknown>)  
-    } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse
+    } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse
 end } def
 
 % array delim print_readably -> _pr_str_args -> new_string
@@ -72,10 +77,26 @@ end } def
     args length 0 gt { %if any elements
         [
             args { %foreach argument in array
-                print_readably _pr_str
+                dup xcheck { %if executable
+                    255 string cvs
+                }{
+                    print_readably _pr_str
+                } ifelse
             } forall 
         ]
         { concatenate delim concatenate } forall
         dup length delim length sub 0 exch getinterval % strip off final delim
     } if
 end } def
+
+% utility function
+/print_dict {
+    (DICT contents:\n) print
+    {
+        (  - ) print
+        exch dup length string cvs print % key
+        (: ) print
+        ==
+    } forall
+} def
+
diff --git a/ps/reader.ps b/ps/reader.ps
index 430f0c9..188a121 100644
--- a/ps/reader.ps
+++ b/ps/reader.ps
@@ -7,7 +7,7 @@
 
 % read_number: read a single number from string/idx
 % string idx -> read_number -> number string new_idx
-/read_number {
+/read_number { 5 dict begin
     %(in read_number\n) print
     /idx exch def
     /str exch def
@@ -26,12 +26,12 @@
 
     str start cnt getinterval cvi % the matched number
     str idx % return: number string new_idx
-} def
+end } def
 
 
 % read_symbol: read a single symbol from string/idx
 % string idx -> read_symbol -> name string new_idx
-/read_symbol {
+/read_symbol { 5 dict begin
     %(in read_symbol\n) print
     /idx exch def
     /str exch def
@@ -51,12 +51,12 @@
 
     str start cnt getinterval cvn % the matched symbol
     str idx % return: symbol string new_idx
-} def
+end } def
 
 
 % read_string: read a single string from string/idx
 % string idx -> read_string -> new_string string new_idx
-/read_string {
+/read_string { 5 dict begin
     %(in read_string\n) print
     /idx exch 1 add def
     /str exch def
@@ -80,12 +80,12 @@
     str start cnt getinterval % the matched string
     (\\") (") replace
     str idx % return: new_string string new_idx
-} def
+end } def
 
 
 % read_atom: read a single atom from string/idx
 % string idx -> read_atom -> int string new_idx
-/read_atom {
+/read_atom { 3 dict begin
     %(in read_atom\n) print
     /idx exch def
     /str exch def
@@ -114,11 +114,11 @@
     }ifelse
 
     % return: atom string new_idx
-} def
+end } def
 
 % read_until: read a list from string/idx until stopchar is found
 % string idx stopchar -> read_until -> list string new_idx
-/read_until {
+/read_until { 3 dict begin
     %(in read_until\n) print
     /stopchar exch def
     /idx exch 1 add def
@@ -135,24 +135,40 @@
     } loop
     ]
     str idx 1 add
-} def
+end } def
 
 % read_spaces: advance idx to the first non-whitespace
 % string idx -> read_form -> string new_idx
-/read_spaces {
+/read_spaces { 3 dict begin
     %(in read_spaces\n) print
     /idx exch def
     /str exch def
     { % loop
         str length idx le { exit } if % EOF, break loop
         /ch str idx get def  % current character
+        %(left1.1:) print str idx str length idx sub getinterval print (\n) print
+        % eliminate comments
+        ch 59 eq { %if ';'
+            { % loop
+                /idx idx 1 add def % increment idx
+                str length idx le { exit } if % EOF, break loop
+                /ch str idx get def  % current character
+                %(left1.2:) print str idx str length idx sub getinterval print (\n) print
+                % if newline then we are done
+                ch 10 eq { exit } if
+            } loop
+            /idx idx 1 add def
+            str length idx le { exit } if % EOF, break loop
+            /ch str idx get def  % current character
+        } if
         % if not whitespace then exit
         ch 32 ne ch 10 ne ch 44 ne and and { exit } if
         /idx idx 1 add def % increment idx
     } loop
 
+    %(left1.3:) print str idx str length idx sub getinterval print (\n) print
     str idx % return: string new_idx
-} def
+end } def
 
 % read_form: read the next form from string start at idx
 % string idx -> read_form -> ast string new_idx
@@ -162,21 +178,12 @@
     /idx exch def
     /str exch def
 
-    idx str length ge { (unexpected EOF) _throw } if % EOF
+    %idx str length ge { (unexpected EOF) _throw } if % EOF
+    idx str length ge { null str idx }{ %if EOF
+
     /ch str idx get def  % current character
-    ch 59 eq { %if ';'
-        { % loop
-            /idx idx 1 add def % increment idx
-            str length idx le { exit } if % EOF, break loop
-            /ch str idx get def  % current character
-            % if newline then add 1 more idx and exit
-            ch 10 eq {
-                /idx idx 1 add def
-                exit
-            } if
-        } loop
-        str idx read_form % recur to get next form
-    }{ ch 39 eq { %if '\''
+    %(LEFT2.1:) print str idx str length idx sub getinterval print (\n) print
+    ch 39 eq { %if '\''
         /idx idx 1 add def
         str idx read_form
         3 -1 roll   /quote exch 2 _list   3 1 roll
@@ -204,23 +211,28 @@
         str idx read_form
         3 -1 roll   /deref exch 2 _list   3 1 roll
     }{ ch 40 eq { %if '('
-        str idx 41 read_until
+        str idx 41 read_until dup /idx exch def
+        %(LEFT2.2:) print str idx str length idx sub getinterval print (\n) print
         3 -1 roll   _list_from_array   3 1 roll
+        %(LEFT2.3:) print str idx str length idx sub getinterval print (\n) print
     }{ ch 41 eq { %elseif ')'
         (unexpected '\)') _throw
-    }{ ch 91 eq { %if '('
-        str idx 93 read_until
+    }{ ch 91 eq { %if '['
+        str idx 93 read_until dup /idx exch def
+        %(LEFT2.4:) print str idx str length idx sub getinterval print (\n) print
         3 -1 roll   _vector_from_array   3 1 roll
     }{ ch 93 eq { %elseif ']'
         (unexpected ']') _throw
     }{ ch 123 eq { %elseif '{'
-        str idx 125 read_until
+        str idx 125 read_until dup /idx exch def
         3 -1 roll   _hash_map_from_array   3 1 roll
     }{ ch 125 eq { %elseif '}'
         (unexpected '}') _throw
     }{ % else
         str idx read_atom
-    } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse
+    } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse
+
+    } ifelse % not EOF
 
     % return: ast string new_idx
 end } def
diff --git a/ps/step4_if_fn_do.ps b/ps/step4_if_fn_do.ps
index cd14b18..952661a 100644
--- a/ps/step4_if_fn_do.ps
+++ b/ps/step4_if_fn_do.ps
@@ -83,27 +83,18 @@ end } def
         }{ /fn* a0 eq { %if fn*
             /a1 ast 1 _nth def
             /a2 ast 2 _nth def
-            <<
-                /_maltype_ /function % user defined function
-                /params null % close over parameters
-                /ast null    % close over ast
-                /env null    % close over environment
-                /data { __self__ fload EVAL }
-            >>
-            dup length dict copy % make an actual copy/new instance
-            dup /params a1 put  % insert closed over a1 into position 2
-            dup /ast a2 put  % insert closed over a2 into position 3
-            dup /env env put % insert closed over env into position 4
-            dup   dup /data get   exch 0 exch put % insert self reference
+            a2 env a1 _mal_function
         }{
             /el ast env eval_ast def
             el _rest el _first % stack: ast function
-            dup _mal_function? { % if user defined function
+            dup _mal_function? { %if user defined function
                 fload % stack: ast new_env
                 EVAL
+            }{ dup _function? { %else if builtin function
+                /data get exec
             }{ %else (regular procedure/function)
-                exec % apply function to args
-            } ifelse
+                (cannot apply native proc!\n) print quit
+            } ifelse } ifelse
         } ifelse } ifelse } ifelse } ifelse } ifelse
     } ifelse
 end } def
@@ -120,7 +111,7 @@ end } def
 
 /RE { READ repl_env EVAL } def
 /REP { READ repl_env EVAL PRINT } def
-/_ref { repl_env 3 1 roll env_set pop } def
+/_ref { _function repl_env 3 1 roll env_set pop } def
 
 core_ns { _ref } forall
 
diff --git a/ps/step5_tco.ps b/ps/step5_tco.ps
index 96c44ee..802f3d3 100644
--- a/ps/step5_tco.ps
+++ b/ps/step5_tco.ps
@@ -90,27 +90,18 @@ end } def
         }{ /fn* a0 eq { %if fn*
             /a1 ast 1 _nth def
             /a2 ast 2 _nth def
-            <<
-                /_maltype_ /function % user defined function
-                /params null % close over parameters
-                /ast null    % close over ast
-                /env null    % close over environment
-                /data { __self__ fload EVAL }
-            >>
-            dup length dict copy % make an actual copy/new instance
-            dup /params a1 put  % insert closed over a1 into position 2
-            dup /ast a2 put  % insert closed over a2 into position 3
-            dup /env env put % insert closed over env into position 4
-            dup   dup /data get   exch 0 exch put % insert self reference
+            a2 env a1 _mal_function
         }{
             /el ast env eval_ast def
             el _rest el _first % stack: ast function
-            dup _mal_function? { % if user defined function
+            dup _mal_function? { %if user defined function
                 fload % stack: ast new_env
                 /loop? true def
+            }{ dup _function? { %else if builtin function
+                /data get exec
             }{ %else (regular procedure/function)
-                exec % apply function to args
-            } ifelse
+                (cannot apply native proc!\n) print quit
+            } ifelse } ifelse
         } ifelse } ifelse } ifelse } ifelse } ifelse
     } ifelse
 
@@ -130,7 +121,7 @@ end } def
 
 /RE { READ repl_env EVAL } def
 /REP { READ repl_env EVAL PRINT } def
-/_ref { repl_env 3 1 roll env_set pop } def
+/_ref { _function repl_env 3 1 roll env_set pop } def
 
 core_ns { _ref } forall
 
diff --git a/ps/step6_file.ps b/ps/step6_file.ps
index 1eff14f..fc12cc1 100644
--- a/ps/step6_file.ps
+++ b/ps/step6_file.ps
@@ -90,27 +90,18 @@ end } def
         }{ /fn* a0 eq { %if fn*
             /a1 ast 1 _nth def
             /a2 ast 2 _nth def
-            <<
-                /_maltype_ /function % user defined function
-                /params null % close over parameters
-                /ast null    % close over ast
-                /env null    % close over environment
-                /data { __self__ fload EVAL }
-            >>
-            dup length dict copy % make an actual copy/new instance
-            dup /params a1 put  % insert closed over a1 into position 2
-            dup /ast a2 put  % insert closed over a2 into position 3
-            dup /env env put % insert closed over env into position 4
-            dup   dup /data get   exch 0 exch put % insert self reference
+            a2 env a1 _mal_function
         }{
             /el ast env eval_ast def
             el _rest el _first % stack: ast function
-            dup _mal_function? { % if user defined function
+            dup _mal_function? { %if user defined function
                 fload % stack: ast new_env
                 /loop? true def
+            }{ dup _function? { %else if builtin function
+                /data get exec
             }{ %else (regular procedure/function)
-                exec % apply function to args
-            } ifelse
+                (cannot apply native proc!\n) print quit
+            } ifelse } ifelse
         } ifelse } ifelse } ifelse } ifelse } ifelse
     } ifelse
 
@@ -130,7 +121,7 @@ end } def
 
 /RE { READ repl_env EVAL } def
 /REP { READ repl_env EVAL PRINT } def
-/_ref { repl_env 3 1 roll env_set pop } def
+/_ref { _function repl_env 3 1 roll env_set pop } def
 
 core_ns { _ref } forall
 
diff --git a/ps/step7_quote.ps b/ps/step7_quote.ps
index 4708aa0..6913bf6 100644
--- a/ps/step7_quote.ps
+++ b/ps/step7_quote.ps
@@ -122,28 +122,19 @@ end } def
         }{ /fn* a0 eq { %if fn*
             /a1 ast 1 _nth def
             /a2 ast 2 _nth def
-            <<
-                /_maltype_ /function % user defined function
-                /params null % close over parameters
-                /ast null    % close over ast
-                /env null    % close over environment
-                /data { __self__ fload EVAL }
-            >>
-            dup length dict copy % make an actual copy/new instance
-            dup /params a1 put  % insert closed over a1 into position 2
-            dup /ast a2 put  % insert closed over a2 into position 3
-            dup /env env put % insert closed over env into position 4
-            dup   dup /data get   exch 0 exch put % insert self reference
+            a2 env a1 _mal_function
         }{
             /el ast env eval_ast def
             el _rest el _first % stack: ast function
-            dup _mal_function? { % if user defined function
+            dup _mal_function? { %if user defined function
                 fload % stack: ast new_env
                 /loop? true def
+            }{ dup _function? { %else if builtin function
+                /data get exec
             }{ %else (regular procedure/function)
-                exec % apply function to args
-            } ifelse
-        } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse  } ifelse 
+                (cannot apply native proc!\n) print quit
+            } ifelse } ifelse
+        } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse 
     } ifelse
 
     loop? not { exit } if
@@ -162,7 +153,7 @@ end } def
 
 /RE { READ repl_env EVAL } def
 /REP { READ repl_env EVAL PRINT } def
-/_ref { repl_env 3 1 roll env_set pop } def
+/_ref { _function repl_env 3 1 roll env_set pop } def
 
 core_ns { _ref } forall
 
diff --git a/ps/step8_macros.ps b/ps/step8_macros.ps
index 330f6f7..286c1ab 100644
--- a/ps/step8_macros.ps
+++ b/ps/step8_macros.ps
@@ -163,28 +163,18 @@ end } def
         }{ /fn* a0 eq { %if fn*
             /a1 ast 1 _nth def
             /a2 ast 2 _nth def
-            <<
-                /_maltype_ /function % user defined function
-                /macro? false % macro flag, false by default
-                /params null % close over parameters
-                /ast null    % close over ast
-                /env null    % close over environment
-                /data { __self__ fload EVAL }
-            >>
-            dup length dict copy % make an actual copy/new instance
-            dup /params a1 put  % insert closed over a1 into position 2
-            dup /ast a2 put  % insert closed over a2 into position 3
-            dup /env env put % insert closed over env into position 4
-            dup   dup /data get   exch 0 exch put % insert self reference
+            a2 env a1 _mal_function
         }{
             /el ast env eval_ast def
             el _rest el _first % stack: ast function
-            dup _mal_function? { % if user defined function
+            dup _mal_function? { %if user defined function
                 fload % stack: ast new_env
                 /loop? true def
+            }{ dup _function? { %else if builtin function
+                /data get exec
             }{ %else (regular procedure/function)
-                exec % apply function to args
-            } ifelse
+                (cannot apply native proc!\n) print quit
+            } ifelse } ifelse
         } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse
       } ifelse
     } ifelse
@@ -205,7 +195,7 @@ end } def
 
 /RE { READ repl_env EVAL } def
 /REP { READ repl_env EVAL PRINT } def
-/_ref { repl_env 3 1 roll env_set pop } def
+/_ref { _function repl_env 3 1 roll env_set pop } def
 
 core_ns { _ref } forall
 
diff --git a/ps/step9_interop.ps b/ps/step9_interop.ps
index 5a7f3ec..f4380da 100644
--- a/ps/step9_interop.ps
+++ b/ps/step9_interop.ps
@@ -177,28 +177,18 @@ end } def
         }{ /fn* a0 eq { %if fn*
             /a1 ast 1 _nth def
             /a2 ast 2 _nth def
-            <<
-                /_maltype_ /function % user defined function
-                /macro? false % macro flag, false by default
-                /params null % close over parameters
-                /ast null    % close over ast
-                /env null    % close over environment
-                /data { __self__ fload EVAL }
-            >>
-            dup length dict copy % make an actual copy/new instance
-            dup /params a1 put  % insert closed over a1 into position 2
-            dup /ast a2 put  % insert closed over a2 into position 3
-            dup /env env put % insert closed over env into position 4
-            dup   dup /data get   exch 0 exch put % insert self reference
+            a2 env a1 _mal_function
         }{
             /el ast env eval_ast def
             el _rest el _first % stack: ast function
-            dup _mal_function? { % if user defined function
+            dup _mal_function? { %if user defined function
                 fload % stack: ast new_env
                 /loop? true def
+            }{ dup _function? { %else if builtin function
+                /data get exec
             }{ %else (regular procedure/function)
-                exec % apply function to args
-            } ifelse
+                (cannot apply native proc!\n) print quit
+            } ifelse } ifelse
         } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse
       } ifelse
     } ifelse
@@ -219,7 +209,7 @@ end } def
 
 /RE { READ repl_env EVAL } def
 /REP { READ repl_env EVAL PRINT } def
-/_ref { repl_env 3 1 roll env_set pop } def
+/_ref { _function repl_env 3 1 roll env_set pop } def
 
 core_ns { _ref } forall
 
diff --git a/ps/stepA_more.ps b/ps/stepA_more.ps
index 5704413..91a1fc7 100644
--- a/ps/stepA_more.ps
+++ b/ps/stepA_more.ps
@@ -213,28 +213,18 @@ end } def
         }{ /fn* a0 eq { %if fn*
             /a1 ast 1 _nth def
             /a2 ast 2 _nth def
-            <<
-                /_maltype_ /function % user defined function
-                /macro? false % macro flag, false by default
-                /params null % close over parameters
-                /ast null    % close over ast
-                /env null    % close over environment
-                /data { __self__ fload EVAL }
-            >>
-            dup length dict copy % make an actual copy/new instance
-            dup /params a1 put  % insert closed over a1 into position 2
-            dup /ast a2 put  % insert closed over a2 into position 3
-            dup /env env put % insert closed over env into position 4
-            dup   dup /data get   exch 0 exch put % insert self reference
+            a2 env a1 _mal_function
         }{
             /el ast env eval_ast def
             el _rest el _first % stack: ast function
-            dup _mal_function? { % if user defined function
+            dup _mal_function? { %if user defined function
                 fload % stack: ast new_env
                 /loop? true def
+            }{ dup _function? { %else if builtin function
+                /data get exec
             }{ %else (regular procedure/function)
-                exec % apply function to args
-            } ifelse
+                (cannot apply native proc!\n) print quit
+            } ifelse } ifelse
         } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse } ifelse
       } ifelse
     } ifelse
@@ -255,11 +245,11 @@ end } def
 
 /RE { READ repl_env EVAL } def
 /REP { READ repl_env EVAL PRINT } def
-/_ref { repl_env 3 1 roll env_set pop } def
+/_ref { _function repl_env 3 1 roll env_set pop } def
 
 core_ns { _ref } forall
 
-(readline) { 0 _nth _readline not { null } if } _ref
+(readline) { 0 _nth _readline not { pop null } if } _ref
 (read-string) { 0 _nth read_str } _ref
 (eval) { 0 _nth repl_env EVAL } _ref
 /slurp { (r) file dup bytesavailable string readstring pop } def
diff --git a/ps/types.ps b/ps/types.ps
index a22246f..2b26582 100644
--- a/ps/types.ps
+++ b/ps/types.ps
@@ -182,7 +182,45 @@ end } def
 
 % Functions
 
-/_mal_function? {
+% block -> _function -> boxed_function
+/_function {
+    <<
+        /_maltype_ /function
+        %/data 5 -1 roll cvlit
+        /data 5 -1 roll
+    >>
+    %%dup length dict copy
+} def
+
+% ast env params -> _mal_function -> boxed_mal_function
+/_mal_function { 
+    <<
+        /_maltype_ /mal_function % user defined function
+        /macro? false % macro flag, false by default
+        /params null % close over parameters
+        /ast null    % close over ast
+        /env null    % close over environment
+        /data { __self__ fload EVAL }  % forward reference to EVAL
+              dup length array copy cvx % actual copy/new instance of block
+    >>
+    % make an actual copy/new instance of dict
+    dup length dict copy % stack: ast env params mal_fn
+    % "Close over" parameters
+    dup 3 -1 roll     % stack: ast env mal_fn mal_fn params
+    /params exch put  % stack: ast env mal_fn
+    dup 3 -1 roll     % stack: ast mal_fn mal_fn env
+    /env exch put     % stack: ast mal_fn
+    dup 3 -1 roll     % stack: mal_fn mal_fn ast
+    /ast exch put     % stack: mal_fn
+
+    % insert self reference into position 0 of data
+    dup /data get     % stack: mal_fn data
+    1 index           % stack: mal_fn data mal_fn
+    0 exch            % stack: mal_fn data 0 mal_fn
+    put               % stack: mal_fn
+} def
+
+/_function? {
     dup type /dicttype eq {
         /_maltype_ get /function eq
     }{
@@ -190,6 +228,14 @@ end } def
     } ifelse
 } def
 
+/_mal_function? {
+    dup type /dicttype eq {
+        /_maltype_ get /mal_function eq
+    }{
+        pop false
+    } ifelse
+} def
+
 % args mal_function -> fload -> ast new_env
 % fload: sets up arguments on the stack for an EVAL call
 /fload {
@@ -199,9 +245,18 @@ end } def
     env_new                  % stack: ast new_env
 } def
 
-% function_or_block -> callable -> block
-% if this is a user defined mal function, get its executable block
-/callable { dup _mal_function? { /data get } if } def
+% function_or_mal_function -> callable -> block
+% if this is a function or mal_function, get its executable block
+/callable {
+    dup _mal_function? { %if mal_function
+        /data get
+    }{ dup _function? { %else if function
+        /data get
+    }{ %else something invalid
+        (callable called on non-function!\n) print quit
+        cvx
+    } ifelse } ifelse
+} def
 
 
 % Lists
diff --git a/tests/incB.mal b/tests/incB.mal
index ed28734..86960c5 100644
--- a/tests/incB.mal
+++ b/tests/incB.mal
@@ -12,3 +12,6 @@
 
 (prn "incB.mal finished")
 "incB.mal return string"
+
+;; ending comment
+
diff --git a/tests/step4_if_fn_do.mal b/tests/step4_if_fn_do.mal
index a4ce46f..4d41380 100644
--- a/tests/step4_if_fn_do.mal
+++ b/tests/step4_if_fn_do.mal
@@ -264,6 +264,9 @@
 ( (fn* () 4) )
 ;=>4
 
+( (fn* (f x) (f x)) (fn* (a) (+ 1 a)) 7)
+;=>8
+
 
 ;; Testing closures
 ( ( (fn* (a) (fn* (b) (+ a b))) 5) 7)
diff --git a/tests/stepA_more.mal b/tests/stepA_more.mal
index f6b01f5..892b592 100644
--- a/tests/stepA_more.mal
+++ b/tests/stepA_more.mal
@@ -117,6 +117,9 @@
 (map? [])
 ;=>false
 
+(get nil "a")
+;=>nil
+
 (get hm1 "a")
 ;=>nil
 
@@ -174,6 +177,9 @@
 (meta (fn* (a) a))
 ;=>nil
 
+(meta +)
+;=>nil
+
 (with-meta [1 2 3] {"a" 1})
 ;=>[1 2 3]
 
@@ -276,6 +282,15 @@
 (swap! a + 3)
 ;=>123
 
+;; Testing swap!/closure interaction
+(def! inc-it (fn* (a) (+ 1 a)))
+(def! atm (atom 7))
+(def! f (fn* [] (swap! atm inc-it)))
+(f)
+;=>8
+(f)
+;=>9
+
 ;;
 ;; Testing read-str and eval
 (read-string "(1 2 (3 4) nil)")