From f0026818378558a91000c3b606f3cbf88c5e6db0 Mon Sep 17 00:00:00 2001
From: Clemens Niederberger <contact@mychemistry.eu>
Date: Wed, 7 Apr 2021 11:41:45 +0200
Subject: [PATCH] counter exercises in a collection

---
 HISTORY                        |  2 ++
 code/xsim.collections.code.tex | 21 ++++++++++++++++++++-
 code/xsim.sty                  | 21 ++++++++++++++++++++-
 3 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/HISTORY b/HISTORY
index 2f501fc..090a264 100644
--- a/HISTORY
+++ b/HISTORY
@@ -189,3 +189,5 @@ HISTORY:
                      solution files
                    - add option <tag>/use-unmatched
                    - document option `blank/fill'
+                   - add counter foreach type and collection that holds the
+                     number of exercises of a type in a collection
diff --git a/code/xsim.collections.code.tex b/code/xsim.collections.code.tex
index 62b8cf0..dd02de5 100644
--- a/code/xsim.collections.code.tex
+++ b/code/xsim.collections.code.tex
@@ -54,8 +54,26 @@
         \xsim_attribute_set:nnn {collection:conditions} {#1} {#2}
         \seq_gput_right:Nn \g__xsim_collections_seq {#1}
         \xsim_new_list:n {collection:#1}
+        \xsim_before_begin_document:n
+          {
+            \xsim_foreach_exercise_type:n
+              {
+                \int_new:c {g_xsim_collection_##1_in_#1_int}
+                \newcounter {total##1in#1}
+              }
+          }
         \xsim_at_end_document:n
-          { \xsim_update_list:n {collection:#1} }
+          {
+            \xsim_update_list:n {collection:#1}
+            \xsim_foreach_exercise_type:n
+              {
+                \xsim_write_to_aux:x
+                  {
+                    \token_to_str:N \setcounter {total##1in#1}
+                      { \int_use:c {g_xsim_collection_##1_in_#1_int} }
+                  }
+              }
+          }
       }
   }
 
@@ -247,6 +265,7 @@
       { \clist_put_right:Nn \l__xsim_tmpa_clist {#1} }
     \xsim_set_property:nnnV {#2} {#3} {collections} \l__xsim_tmpa_clist
     \xsim_add_to_list:nn {collection:#1} {#2-#3}
+    \int_gincr:c {g_xsim_collection_#2_in_#1_int}
   }
 
 % ----------------------------------------------------------------------------
diff --git a/code/xsim.sty b/code/xsim.sty
index 4303806..bdb0e0e 100644
--- a/code/xsim.sty
+++ b/code/xsim.sty
@@ -3635,8 +3635,26 @@
         \xsim_attribute_set:nnn {collection:conditions} {#1} {#2}
         \seq_gput_right:Nn \g__xsim_collections_seq {#1}
         \xsim_new_list:n {collection:#1}
+        \xsim_before_begin_document:n
+          {
+            \xsim_foreach_exercise_type:n
+              {
+                \int_new:c {g_xsim_collection_##1_in_#1_int}
+                \newcounter {total##1in#1}
+              }
+          }
         \xsim_at_end_document:n
-          { \xsim_update_list:n {collection:#1} }
+          {
+            \xsim_update_list:n {collection:#1}
+            \xsim_foreach_exercise_type:n
+              {
+                \xsim_write_to_aux:x
+                  {
+                    \token_to_str:N \setcounter {total##1in#1}
+                      { \int_use:c {g_xsim_collection_##1_in_#1_int} }
+                  }
+              }
+          }
       }
   }
 
@@ -3828,6 +3846,7 @@
       { \clist_put_right:Nn \l__xsim_tmpa_clist {#1} }
     \xsim_set_property:nnnV {#2} {#3} {collections} \l__xsim_tmpa_clist
     \xsim_add_to_list:nn {collection:#1} {#2-#3}
+    \int_gincr:c {g_xsim_collection_#2_in_#1_int}
   }
 
 % ----------------------------------------------------------------------------