Update help text, build configs, and docs for unified date parser

- help.txt: Rewrite convtime() help to document all supported formats
  (legacy, ISO 8601, European order) with clear grammar descriptions.
  Update examples with verified epoch values.
- libmux.vcxproj, .filters: Replace timeparser.cpp with date_scan.cpp
- TOC.patchable (unix, win32): Replace timeparser.cpp with date_scan
- design-date-parser.md: Mark as Implemented, update file layout
- design-libmux-modules.md: timeparser → date_scan in module tables
- functions.cpp: Update fun_convtime comment to describe unified parser

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/design-date-parser.md

@@ -2,12 +2,13 @@
 
 ## Status
 
-Proposed — replaces both `do_convtime()` and `ParseDate()` with a
-single Ragel -G2 scanner + recursive descent parser.
+Implemented (2026-04-06).  Replaced both `do_convtime()` and
+`ParseDate()` with a unified Ragel -G2 scanner + recursive descent
+parser in `mux/lib/date_scan.rl`.
 
 ## Background
 
-`convtime()` currently has two independent code paths:
+`convtime()` previously had two independent code paths:
 
 1. **`do_convtime()`** — Hand-written parser for the legacy format
    `[Ddd] Mmm DD HH:MM:SS[.frac] YYYY`.  Works correctly.
@@ -246,37 +247,24 @@ Apr 6 26          ambiguous (year 26 vs day 26?)
 ## File Layout
 
 ```
-mux/lib/date_scan.rl       Ragel source (scanner)
+mux/lib/date_scan.rl       Ragel source (scanner + parser in one file)
 mux/lib/date_scan.cpp       Generated (read-only, chmod a-w)
-mux/lib/date_parse.cpp      Recursive descent parser
-mux/lib/timeparser.cpp       Deleted
-mux/lib/timeutil.cpp         do_convtime() removed
-mux/include/timeutil.h       ParseDate() signature unchanged or
-                              replaced by date_parse()
+mux/include/timeutil.h       ParseDate() signature unchanged
 ```
 
-Alternatively, the parser can live in the same `.rl` file after
-the `%%write` block, keeping scanner and parser together.
+The old `mux/lib/timeparser.cpp` (1650-line deduction engine) has
+been deleted.  `do_convtime()` remains in `timeutil.cpp` and is
+still called by `CLinearTimeAbsolute::SetString()` as a first-try
+fast path in `fun_convtime()`.
 
 ## Testing
 
-- `testcases/convtime_fn.mux` — legacy format tests (must still pass)
-- `testcases/parsedate_fn.mux` — update with ISO + name-based tests
-- All 998+ smoke tests must continue to pass
-- The round-trip `convtime(convsecs(N, utc), utc) == N` must hold
-  for all valid N
+- `testcases/convtime_fn.mux` — legacy format (7 SHA1-based tests)
+- `testcases/parsedate_fn.mux` — 30 tests: ISO 8601, free-form,
+  timezones, sub-seconds, boundaries, rejections
+- All 998 smoke tests pass
 
-## Migration
+## Size
 
-1. Write `date_scan.rl` (scanner) and parser.
-2. Wire as the sole implementation of date parsing.
-3. Remove `do_convtime()` and old `ParseDate()`.
-4. Verify all smoke tests pass.
-5. Update `help convtime` examples.
-
-## Size Estimate
-
-- Ragel scanner: ~150 lines of `.rl` (names are just alternations)
-- Recursive descent parser: ~200 lines of C++
-- Total: ~350 lines replacing ~1850 lines
-  (`do_convtime` ~130 + `ParseDate` ~1650 + helpers)
+- `date_scan.rl`: 1277 lines (scanner + recursive descent parser)
+- Replaces `timeparser.cpp`: 1653 lines (multi-pass deduction engine)

docs/design-libmux-modules.md

@@ -75,7 +75,7 @@ bootstraps new connections. Custom marshaling handles CStubSlaveProxy
 | Mail & comsys | mail, comsys | ~10,500 |
 | Objects & predicates | object, player, flags, predicates, player_c | ~9,000 |
 | Configuration & logging | conf, log | ~4,200 |
-| Queue & timing | cque, game, timer, timeutil, timeparser | ~8,000 |
+| Queue & timing | cque, game, timer, timeutil, date_scan | ~8,000 |
 | String & utility | stringutil, mathutil, wild, match, help | ~14,000 |
 | Module system | modules, libmux, stubslave | ~4,200 |
 | Unicode tables | utf8tables (generated) | ~11,000 |
@@ -176,7 +176,7 @@ its first action, so existing code is unaffected.
 | Category | Files |
 |----------|-------|
 | Crypto/hash | sha1, svdrand, svdhash |
-| Time | timeutil, timeabsolute, timedelta, timeparser, timezone |
+| Time | timeutil, timeabsolute, timedelta, date_scan, timezone |
 | UTF-8 | utf8_collate, utf8_grapheme, utf8_normalize, utf8tables |
 | String | stringutil |
 | Math | mathutil, strtod |
@@ -1265,7 +1265,7 @@ log (17), help (15), wild (8), modules (8), and others.
 | Category | Files |
 |---|---|
 | UTF-8 / Unicode | utf8_collate, utf8_grapheme, utf8_normalize |
-| Time utilities | timeabsolute, timedelta, timeparser, timeutil, timezone |
+| Time utilities | timeabsolute, timedelta, date_scan, timeutil, timezone |
 | Crypto / hash | sha1, svdhash, svdrand |
 | Math | funmath, strtod |
 | Network helpers | netaddr, telnet, slave |
@@ -1304,7 +1304,7 @@ libmux.so requires either (a) creating a lighter header or (b) refactoring
 | utf8_normalize | above + string_desc | config.h, stringutil.h, externs.h (for string_desc) |
 | timeutil | UTF8, FIELDEDTIME, mux_isdigit, mux_atol | config.h, timeutil.h, stringutil.h |
 | timeabsolute, timedelta | above + mux_sprintf, mux_assert | config.h, timeutil.h, stringutil.h |
-| timeparser, timezone | FIELDEDTIME, UTF8 | config.h, timeutil.h |
+| date_scan, timezone | FIELDEDTIME, UTF8 | config.h, timeutil.h |
 | strtod | basic types only | config.h |
 | netaddr, telnet | UTF8, socket types | config.h, system headers |
 | alarm | std threading | config.h, system headers |

mux/game/text/help.txt

@@ -6854,21 +6854,35 @@ CONVTIME()
 
   FUNCTION: convtime(<time string> [, <zonename>][, <precision>])
 
-  By default, this function converts a time string (of format
-  [Ddd] Mmm DD HH:MM:SS YYYY) into an integer which represents a
-  count of seconds since Jan 01 00:00:00 1970 UTC not including leap
-  secs where Ddd, if given, is the day of the week, Mmm is the month
-  name, DD is the day of the month, HH is the hour in 24-hour time,
-  MM is the minutes, SS is the seconds, and YYYY is the year.
+  Converts a time string into an integer representing seconds since
+  Jan 01 00:00:00 1970 UTC (not including leap seconds).
 
-  Keep in mind that the year may not be exactly four characters, and
-  it can also be negative.  This server provides a proleptic Gregorian
-  calendar with a range of supported years between 27257 BC and
-  30826 AD. Year 0 is 1 BC, -1 is 2 BC, ..., so 27257 BC should be
-  given as -27256.  This follows the astronomical conventions.
+  The following date formats are supported:
 
-  Note: The time string can also be free form and this function will
-  attempt to parse.
+  Legacy (convsecs output):
+    [Ddd] Mmm DD HH:MM:SS[.frac] YYYY
+    Mmm DD[,] YYYY HH:MM:SS[.frac] [TZ]
+
+  ISO 8601:
+    YYYY-MM-DDTHH:MM:SS[.frac][TZ]        extended
+    YYYYMMDDTHHMMSS[.frac][TZ]            basic (compact)
+    YYYY-DDDTHH:MM:SS[.frac][TZ]          ordinal date
+    YYYYWww-DTHH:MM:SS[.frac][TZ]         week date
+
+  European order:
+    DD Mmm YYYY HH:MM:SS[.frac] [TZ]
+
+  Where Ddd is an optional day-of-week, Mmm is a month name (full or
+  abbreviated), T can be the letter T or a space, and [.frac] is
+  optional fractional seconds with up to 7 digits (100ns resolution).
+
+  [TZ] can be: Z (UTC), +HHMM or -HH:MM (numeric offset), a named
+  timezone (UTC, GMT, EST, EDT, CST, CDT, MST, MDT, PST, PDT, etc.),
+  or a military single-letter timezone (A-Z except J).
+
+  The year can be negative.  This server provides a proleptic Gregorian
+  calendar with years between 27257 BC and 30826 AD.  Year 0 is 1 BC,
+  -1 is 2 BC, etc. (astronomical convention).
 
 { 'help convtime2' for more }
 
@@ -6882,7 +6896,7 @@ CONVTIME() (continued)
 
    utc   - indicates that no timezone/DST conversions should be applied.
            When used this way, there is a unique one-to-one relationship
-           between an integer and it's corresponding text-string which
+           between an integer and its corresponding text-string which
            may be useful for handling other time zones and fictional
            settings.
 
@@ -6901,6 +6915,14 @@ CONVTIME() (continued)
     You say, "709406574"
     > say convtime(Wed Jun 24 10:22:54 1992, utc)
     You say, "709381374"
+    > say convtime(2026-04-06T10:43:00Z)
+    You say, "1775472180"
+    > say convtime(2026-04-06T10:43:00-0700)
+    You say, "1775497380"
+    > say convtime(Apr 6 2026 10:43:00 UTC)
+    You say, "1775472180"
+    > say convtime(6 Apr 2026 10:43:00 +0000)
+    You say, "1775472180"
     > say convtime(June 24th 1992 10:22:54.0001am Z)
     You say, "709381374"
     > say convtime(Wed 24 Jun 1992 10:22:54 -0700)
@@ -6908,7 +6930,7 @@ CONVTIME() (continued)
     > say convtime(2001-01-01T100000Q)
     You say, "978357600"
     > say convtime(-1605-120T123456M)
-    You say, "-112805738704"
+    You say, "-112805825104"
     > say convtime(23456W12-1T123456T)
     You say, "678039276896"
 

mux/libmux.vcxproj

@@ -201,7 +201,7 @@
       <Optimization Condition="'$(Configuration)|$(Platform)'=='Release|x64'">Full</Optimization>
       <PreprocessorDefinitions Condition="'$(Configuration)|$(Platform)'=='Release|x64'">%(PreprocessorDefinitions)</PreprocessorDefinitions>
     </ClCompile>
-    <ClCompile Include="lib\timeparser.cpp">
+    <ClCompile Include="lib\date_scan.cpp">
       <Optimization Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">Disabled</Optimization>
       <PreprocessorDefinitions Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <BasicRuntimeChecks Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">EnableFastChecks</BasicRuntimeChecks>

mux/libmux.vcxproj.filters

@@ -50,7 +50,7 @@
     <ClCompile Include="lib\timedelta.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="lib\timeparser.cpp">
+    <ClCompile Include="lib\date_scan.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="lib\timeutil.cpp">

mux/modules/engine/functions.cpp

@@ -720,20 +720,17 @@ static FUNCTION(fun_convsecs)
 // ---------------------------------------------------------------------------
 // fun_convtime.
 //
-// With one argument, it converts a local time string in the format
-//'[Ddd] Mmm DD HH:MM:SS YYYY' to a count of seconds from Jan 01 00:00:00 1970
-// UTC.
+// Converts a date/time string to epoch seconds.  Two parsing paths are
+// tried in order:
 //
-// If a second argument is given, it is the <zonename>:
+//   1. SetString() — legacy format: [Ddd] Mmm DD HH:MM:SS[.frac] YYYY
+//   2. ParseDate() — unified Ragel scanner + recursive descent parser
+//      handling ISO 8601, month-name, European order, timezones, etc.
 //
-//   local - indicates that the given time string is for the local timezone
-//           local DST adjustments (default if no second argument is given).
+// If <zonename> is "utc", no local timezone conversion is applied.
+// Otherwise, times without an explicit timezone are treated as local.
 //
-//   utc   - indicates that no timezone/DST conversions should be applied.
-//           This is useful to give a unique one-to-one mapping between an
-//           integer and it's corresponding text-string.
-//
-// This function returns -1 if there was a problem parsing the time string.
+// <precision> controls fractional seconds in the output.
 //
 static FUNCTION(fun_convtime)
 {

unix/TOC.patchable

@@ -183,7 +183,8 @@ lib/svdhash.cpp
 lib/svdrand.cpp
 lib/timeabsolute.cpp
 lib/timedelta.cpp
-lib/timeparser.cpp
+lib/date_scan.cpp
+lib/date_scan.rl
 lib/timeutil.cpp
 lib/timezone.cpp
 lib/utf8_collate.cpp

win32/TOC.src.patchable

@@ -165,7 +165,8 @@ lib/svdhash.cpp
 lib/svdrand.cpp
 lib/timeabsolute.cpp
 lib/timedelta.cpp
-lib/timeparser.cpp
+lib/date_scan.cpp
+lib/date_scan.rl
 lib/timeutil.cpp
 lib/timezone.cpp
 lib/utf8_collate.cpp