From 2727b3d90f190dee4687b0e514b3b8301a5ed6b4 Mon Sep 17 00:00:00 2001
From: Max Horn <max@quendi.de>
Date: Thu, 11 Dec 2025 16:58:36 +0100
Subject: [PATCH] Add AUTODOC_ParseDate

Using code formerly in AUTODOC_FormatDate
---
 gap/ToolFunctions.gd |  1 +
 gap/ToolFunctions.gi | 50 ++++++++++++++++++++++++++------------------
 tst/misc.tst         | 10 +++++++++
 3 files changed, 41 insertions(+), 20 deletions(-)

diff --git a/gap/ToolFunctions.gd b/gap/ToolFunctions.gd
index e2fe7f52..9f48666c 100644
--- a/gap/ToolFunctions.gd
+++ b/gap/ToolFunctions.gd
@@ -17,3 +17,4 @@ DeclareGlobalFunction( "AUTODOC_Diff" );
 DeclareGlobalFunction( "AUTODOC_TestWorkSheet" );
 
 DeclareGlobalFunction( "AUTODOC_FormatDate" );
+DeclareGlobalFunction( "AUTODOC_ParseDate" );
diff --git a/gap/ToolFunctions.gi b/gap/ToolFunctions.gi
index fa9fcb25..39a13208 100644
--- a/gap/ToolFunctions.gi
+++ b/gap/ToolFunctions.gi
@@ -218,6 +218,34 @@ function(ws)
     od;
 end);
 
+# Parse a date given as a string. Currently only supports the two formats
+# allowed in PackageInfo.g, namely "DD/MM/YYYY" or "YYYY-MM-DD". Returns a
+# record with entries `year`, `month`, `day` bound to the corresponding
+# integers extracted from the input string.
+#
+# Returns `fail` if the input could not be parsed.
+InstallGlobalFunction( AUTODOC_ParseDate,
+function(date)
+    local day, month, year;
+    if Length(date) <> 10 then
+        return fail;
+    fi;
+    if date{[3,6]} = "//" then
+        day := Int(date{[1,2]});
+        month := Int(date{[4,5]});
+        year := Int(date{[7..10]});
+    elif date{[5,8]} = "--" then
+        day := Int(date{[9,10]});
+        month := Int(date{[6,7]});
+        year := Int(date{[1..4]});
+    else
+        return fail;
+    fi;
+    if day = fail or month = fail or year = fail then
+        return fail;
+    fi;
+    return rec( day := day, month := month, year := year );
+end);
 
 BindGlobal("AUTODOC_months", MakeImmutable([
     "January", "February", "March",
@@ -226,7 +254,6 @@ BindGlobal("AUTODOC_months", MakeImmutable([
     "October", "November", "December"
 ]));
 
-
 # Format a date into a human readable string; a date may consist of only
 # a year; or a year and a month; or a year, month and day. Dates are
 # formatted as "2019", resp. "February 2019" resp. "5 February 2019".
@@ -243,24 +270,7 @@ function(arg)
     if Length(arg) = 1 and IsRecord(arg[1]) then
         date := ShallowCopy(arg[1]);
     elif Length(arg) = 1 and IsString(arg[1]) then
-        if Length(arg[1]) = 10 then
-            date := arg[1];
-            if date{[3,6]} = "//" then
-                date := rec(
-                            day := Int(date{[1,2]}),
-                            month := Int(date{[4,5]}),
-                            year := Int(date{[7..10]}),
-                        );
-            elif date{[5,8]} = "--" then
-                date := rec(
-                            year := Int(date{[1..4]}),
-                            month := Int(date{[6,7]}),
-                            day := Int(date{[9,10]}),
-                        );
-            else
-                Unbind(date);
-            fi;
-        fi;
+        date := AUTODOC_ParseDate(arg[1]);
     elif Length(arg) in [1..3] then
         date := rec();
         date.year := arg[1];
@@ -271,7 +281,7 @@ function(arg)
             date.day := arg[3];
         fi;
     fi;
-    if not IsBound(date) then
+    if not IsBound(date) or date = fail then
         Error("Invalid arguments");
     fi;
 
diff --git a/tst/misc.tst b/tst/misc.tst
index 94c45c92..b47b5735 100644
--- a/tst/misc.tst
+++ b/tst/misc.tst
@@ -13,6 +13,16 @@ gap> AUTODOC_SetIfMissing(r, "foo", 2);
 gap> r;
 rec( foo := 1 )
 
+#
+# AUTODOC_ParseDate
+#
+gap> AUTODOC_ParseDate("2019-03-01");
+rec( day := 1, month := 3, year := 2019 )
+gap> AUTODOC_ParseDate("01/03/2019");
+rec( day := 1, month := 3, year := 2019 )
+gap> AUTODOC_ParseDate("01.03.2019");
+fail
+
 #
 # AUTODOC_FormatDate
 #