9 files changed, 62 insertions, 5 deletions

diff --git a/README.md b/README.md
index 2971b4c..2cce7bf 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,11 @@ Unlimited Register Machine in OCaml.
 
 ## Usage
 
-TODO: describe usage of the `urm` program.
+```
+./urm <run | trace> <program file> <initial register state file>
+```
+
+Examples programs are provided in the `examples` folder.
 
 
 ## Authors
diff --git a/examples/add.reg b/examples/add.reg
new file mode 100644
index 0000000..c24e1f9
--- /dev/null
+++ b/examples/add.reg
@@ -0,0 +1,2 @@
+1 2
+2 3
diff --git a/examples/add.urm b/examples/add.urm
new file mode 100644
index 0000000..d11eff7
--- /dev/null
+++ b/examples/add.urm
@@ -0,0 +1,11 @@
+ZERO 0
+ZERO 3
+JUMP 1 3 6
+SUCC 0
+SUCC 3
+JUMP 3 3 2
+ZERO 3
+JUMP 2 3 11
+SUCC 0
+SUCC 3
+JUMP 3 3 7
diff --git a/main.ml b/main.ml
index 1bb6704..2f8d57c 100644
--- a/main.ml
+++ b/main.ml
@@ -9,3 +9,22 @@ open Instptr
 open Reg
 open Urm
 
+let exec_with_resource func filename =
+  let file = open_in filename in
+  let res = func file in
+  close_in file; res
+
+let read_prgm = exec_with_resource (fun f -> string_of_file f |> program_of_string)
+let read_regs = exec_with_resource (fun f -> string_of_file f |> regs_of_string)
+let run run_func prgm regs = urm_mk prgm regs |> run_func |> regs_string |> print_endline
+
+let run_mode_of_string = function
+  | "run" -> urm_run
+  | "trace" -> urm_run_trace
+  | _ -> failwith "Invalid run mode"
+
+let () = match Sys.argv with
+  | [| _; "run-tests" |] -> () (* handled in test files *)
+  | [| _; mode; prgm; regs |] -> run (run_mode_of_string mode) (read_prgm prgm) (read_regs regs)
+  | _ -> print_endline "Usage: urm <run-tests | run <prgmfile> <regfile> | trace <prgmfile> <regfile>>"
+
diff --git a/makefile b/makefile
index 2ccd250..6345a40 100644
--- a/makefile
+++ b/makefile
@@ -6,7 +6,8 @@ SOURCES = \
   parser.mli parser.ml \
   instptr.mli instptr.ml \
   reg.mli reg.ml \
-  urm.mli urm.ml urm_test.ml
+  urm.mli urm.ml urm_test.ml \
+  main.ml
 
 OCAMLMAKEFILE = /usr/share/ocamlmakefile/OCamlMakefile
 include $(OCAMLMAKEFILE)
diff --git a/parser.ml b/parser.ml
index 72042d2..1f367d1 100644
--- a/parser.ml
+++ b/parser.ml
@@ -20,7 +20,13 @@ let rec program_of_lex = function
     | "jump" :: arg_1 :: arg_2 :: arg_3 :: tail -> (Jump ((int_of_string arg_1), (int_of_string arg_2), (int_of_string arg_3))) :: (program_of_lex tail)
     | _ -> raise Syntax_error
 
-let program_of_string str =
-  let lex = Str.split (Str.regexp "[\t\n(),]+") str
-  in List.iter (fun s -> print_string s; print_newline ()) lex; program_of_lex lex
+(* FIXME: reject multiple definition of a single register *)
+let rec regs_of_lex = function
+  | [] -> []
+  | regnum :: regvalue :: tail -> Reg (int_of_string regnum, int_of_string regvalue) :: (regs_of_lex tail)
+  | _ -> raise Syntax_error
+
+let seq_from_string lexer_func str =  Str.split (Str.regexp "[\t\n(), ]+") str |> lexer_func
+let program_of_string = seq_from_string program_of_lex
+let regs_of_string = seq_from_string regs_of_lex
 
diff --git a/parser.mli b/parser.mli
index d210396..f7609f9 100644
--- a/parser.mli
+++ b/parser.mli
@@ -11,5 +11,12 @@ val string_of_file : in_channel -> string
 (* Converts lexemes into instructions. *)
 val program_of_lex : string list -> urmcmd list
 
+(* Converts lexemes into registers. *)
+val regs_of_lex : string list -> reg list
+
 (* Parses the string representation of a program. *)
 val program_of_string : string -> urmcmd list
+
+(* Parses the string representation of serialized registers. *)
+val regs_of_string : string -> reg list
+
diff --git a/reg.ml b/reg.ml
index c452282..45bbb4b 100644
--- a/reg.ml
+++ b/reg.ml
@@ -8,6 +8,7 @@ open Common
 let reg_idx (Reg(idx, _)) = idx
 let reg_val (Reg(_, value)) = value
 let reg_compar l r = (reg_val l) - (reg_val r)
+let reg_string (Reg (index, value)) = (string_of_int index) ^ ": " ^ (string_of_int value)
 
 let regs_get reglist index =
   List.find (fun (Reg(idx, _)) -> idx = index) reglist |> reg_val
@@ -15,3 +16,5 @@ let regs_get reglist index =
 let regs_set reglist index value =
   Reg(index, value) :: List.filter (fun (Reg(idx, _)) -> idx != index) reglist
 
+let rec regs_string reglist = List.map (reg_string) reglist |> String.concat ", "
+
diff --git a/reg.mli b/reg.mli
index 15d53de..f5e41a0 100644
--- a/reg.mli
+++ b/reg.mli
@@ -21,3 +21,7 @@ val regs_get : reg list -> regidx -> regval
 (* Set the value of the register to value,
  * or creates it to the value specified if it does not exist *)
 val regs_set : reg list -> regidx -> regval -> reg list
+
+(* Returns the string representation of a register list. *)
+val regs_string : reg list -> string
+