Allow '-' to mean read from stdin.

[ocaml-csv.git] / csv.ml

diff --git a/csv.ml b/csv.ml
index 6ca424b..0b6e649 100644 (file)
--- a/csv.ml
+++ b/csv.ml
@@ -1,6 +1,6 @@
 (* csv.ml - comma separated values parser
  *
- * $Id: csv.ml,v 1.11 2006-07-19 09:41:58 rich Exp $
+ * $Id: csv.ml,v 1.14 2006-11-24 15:49:24 rich Exp $
  *)
 
 (* The format of CSV files:
@@ -42,6 +42,11 @@
 
 open Printf
 
+(* Uncomment the next line to enable Extlib's List function.  These
+ * avoid stack overflows on really huge CSV files.
+ *)
+(*open ExtList*)
+
 type t = string list list
 
 exception Bad_CSV_file of string
@@ -173,10 +178,13 @@ let load_in ?separator chan =
   List.rev !csv
 
 let load ?separator filename =
-  let chan = open_in filename in
+  let chan, close =
+    match filename with
+    | "-" -> stdin, false
+    | filename -> open_in filename, true in
   let csv = load_in ?separator chan in
-  close_in chan;
-  csv 
+  if close then close_in chan;
+  csv
 
 let trim ?(top=true) ?(left=true) ?(right=true) ?(bottom=true) csv =
   let rec empty_row = function
@@ -299,6 +307,27 @@ let rec compare (csv1 : t) csv2 =
       let c = compare_row [] y in
       if c <> 0 then c else compare [] ys
 
+(* Concatenate - arrange left to right. *)
+let rec concat = function
+  | [] -> []
+  | [csv] -> csv
+  | left_csv :: csvs ->
+      (* Concatenate the remaining CSV files. *)
+      let right_csv = concat csvs in
+
+      (* Set the height of the left and right CSVs to the same. *)
+      let nr_rows = max (lines left_csv) (lines right_csv) in
+      let left_csv = set_rows nr_rows left_csv in
+      let right_csv = set_rows nr_rows right_csv in
+
+      (* Square off the left CSV. *)
+      let left_csv = square left_csv in
+
+      (* Prepend the right CSV rows with the left CSV rows. *)
+      List.map (
+       fun (left_row, right_row) -> List.append left_row right_row
+      ) (List.combine left_csv right_csv)
+
 let to_array csv =
   Array.of_list (List.map Array.of_list csv)