add a built in capitalize function

README.md

@@ -358,6 +358,24 @@ because 123z does not form a valid identifier.
 
 `CONCAT(a,b)` is roughly equivalent to `a##b` in cpp syntax.
 
+CAPITALIZE
+---------------
+
+`CAPITALIZE()` is a predefined macro that takes one argument,
+removes any leading and trailing whitespace, reduces each internal
+whitespace sequence to a single space character and produces
+a valid OCaml identifer with first character.
+
+For example,
+```ocaml
+#define EVENT(n,ty) external CONCAT(on,CAPITALIZE(n)) : ty = STRINGIFY(n) [@@bs.val] 
+EVENT(exit, unit -> unit)
+```
+is expanded into:
+
+```ocaml
+external  onExit  :  unit -> unit = "exit" [@@bs.val]
+```
 
 Stringification
 ---------------

cppo_eval.ml

@@ -23,6 +23,13 @@ let builtins = [
                                  `Ident (dummy_loc, "y", None))],
                        env)
             );
+  "CAPITALIZE", (fun env ->
+    `Defun (dummy_loc, "CAPITALIZE",
+            ["x"],
+            [`Capitalize (`Ident (dummy_loc, "x", None))],
+            env)
+  );
+
 ]
 
 let is_reserved s =
@@ -84,7 +91,11 @@ let trim_and_compact_string s =
   let buf = Buffer.create (String.length s) in
   trim_and_compact buf s;
   Buffer.contents buf
-
+let trim_compact_and_capitalize_string s =
+  let buf = Buffer.create (String.length s) in
+  trim_and_compact buf s;
+  String.capitalize (Buffer.contents buf)
+
 let is_ident s =
   let len = String.length s in
   len > 0
@@ -442,7 +453,7 @@ let rec include_file g loc rel_file env =
 and expand_list ?(top = false) g env l =
   List.fold_left (expand_node ~top g) env l
 
-and expand_node ?(top = false) g env0 x =
+and expand_node ?(top = false) g env0 (x : node) =
   match x with
       `Ident (loc, name, opt_args) ->
 
@@ -610,6 +621,20 @@ and expand_node ?(top = false) g env0 x =
         g.enable_loc := enable_loc0;
         env0
 
+    | `Capitalize (x : node) ->
+        let enable_loc0 = !(g.enable_loc) in
+        g.enable_loc := false;
+        let buf0 = g.buf in
+        let local_buf = Buffer.create 100 in
+        g.buf <- local_buf;
+        ignore (expand_node g env0 x);
+        let xs = Buffer.contents local_buf in
+        let s = trim_compact_and_capitalize_string xs in
+          (* stringify buf0 (Buffer.contents local_buf); *)
+        Buffer.add_string buf0 s ;
+        g.buf <- buf0;
+        g.enable_loc := enable_loc0;
+        env0
     | `Concat (x, y) ->
         let enable_loc0 = !(g.enable_loc) in
         g.enable_loc := false;

cppo_types.ml

@@ -58,6 +58,7 @@ and node =
     | `Text of (loc * bool * string) (* bool is true for space tokens *)
     | `Seq of node list
     | `Stringify of node
+    | `Capitalize of node
     | `Concat of (node * node)
     | `Line of (loc * string option * int)
     | `Current_line of loc

test/Makefile

@@ -1,4 +1,4 @@
-TESTS = ext comments cond tuple paren_arg unmatched version
+TESTS = ext comments cond tuple paren_arg unmatched version capital
 .PHONY: all clean $(TESTS)
 
 all: $(TESTS)
@@ -36,5 +36,8 @@ unmatched:
 version:
 	../cppo -V X:123.05.2-alpha.1+foo-2.1 version.cppo > version.out
 
+capital:
+	../cppo $@.cppo > $@.out
+	diff -u $@.ref $@.out
 clean:
 	rm -f *~ *.out

test/capital.cppo

@@ -0,0 +1,6 @@
+
+
+#define EVENT(n,ty) external CONCAT(on,CAPITALIZE(n)) : ty = STRINGIFY(n) [@@bs.val] 
+
+
+EVENT(exit, unit -> unit)

test/capital.ref

@@ -0,0 +1,6 @@
+
+
+
+
+# 6 "capital.cppo"
+ external  onExit  :  unit -> unit = "exit" [@@bs.val]