From 4248630df9fe87e1fc3c2c62e3dcfec4cae347ba Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 12:40:52 -0700
Subject: [PATCH 01/22] Compare three remaining options (draft)

---
 exploration/syntax-exploration-2.md | 184 ++++++++++++++++++++++++++++
 1 file changed, 184 insertions(+)
 create mode 100644 exploration/syntax-exploration-2.md

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
new file mode 100644
index 0000000000..e06be24c20
--- /dev/null
+++ b/exploration/syntax-exploration-2.md
@@ -0,0 +1,184 @@
+# Syntax Exploration v2
+
+In the 2023-10-16 teleconference, we narrowed the options being considered for text-mode syntax to "1a", "2a", and "3a". 
+Each of these syntax candidates has been adjusted based on our conversation.
+
+One open issue, separately considered here, is the use of an additional sigil for some of the syntaxes.
+We have generally used `#` as the placeholder for this sigil in the previous iteration.
+
+
+## Comparison Matrix
+
+... goes here...
+
+## Candidates
+
+### Candidate 1a
+
+**Description:** Invert for Text Mode, distinguish statements from placeholders
+
+- Placeholders and expressions use `{`/`}`:
+  > `{$var}`, `{unquoted}`, `{|quoted|}`, `{$var :function}`
+- Non-placeholders use `{#`/`}`:
+  > `{#input $user}`, `{#local $var=$foo :expr}`, `{#match {$foo}}`, `{#when * *}`
+
+The use of `#` as the sigil is intentional here.
+This sigil might be replaced, but does not require additional escaping, as code is enclosed in `{`/`}`.
+Note that the `#` sigil might also be considered to be part of the keyword, e.g. `#when`, `#local` vs.
+allowing whitespace to appear between them.
+
+Patterns in this syntax are generally unquoted,
+but MAY be quoted with the 2023-10-09 consensus `{{`/`}}` quotes.
+
+ASCII whitespace trimming is assumed, but is a hot topic.
+
+**Examples**
+```
+Hello world!
+```
+```
+Hello {$user}
+```
+```
+{#input $user :person type=informal}
+Hello {$user}
+
+{#input $user :person type=informal}Hello {$user}
+```
+```
+{#input $var :function option=value}
+{#local $foo = $bar :function option=value}
+Hello {$var}, you have a {$foo}
+
+{#input $var :function option=value}{#local $foo = $bar :function option=value}Hello {$var}, you have a {$foo}
+```
+```
+{#match {$foo} {$bar}}
+{#when foo bar} Hello {$foo} you have a {$var}
+{#when * *} {$foo} hello you have a {$var}
+
+{#match {$foo} {$bar}}{#when foo bar}Hello {$foo} you have a {$var}{#when * *}{$foo} hello you have a {$var}
+```
+```
+{#match {$foo :function option=value} {$bar :function option=value}}
+{#when a b} {{  {$foo} is {$bar}  }}
+{#when x y} {{  {$foo} is {$bar}  }}
+{#when * *} {|  |}{$foo} is {$bar}{|  |}
+
+{#match {$foo :function option=value} {$bar :function option=value}}{#when a b} {{  {$foo} is {$bar}  }}{#when x y} {{  {$foo} is {$bar}  }}{#when * *} {|  |}{$foo} is {$bar}{|  |}
+```
+
+### Candidate 2a
+
+**Description**: Text First, Current Syntax for "Complex" Messages
+
+Starts in text mode, but switches to the current "code-mode" syntax for any message containing declarations or selectors.
+
+- "Simple" messages (lacking declarations or selectors) are unquoted patterns.
+- Patterns with declarations (`input`, `local`), selectors (`match`/`when`) or both quote all patterns.
+- Pattern whitespace is always significant.
+  Note that "pattern whitespace" is only that whitespace that appears inside the quoting `{`/`}`
+  for quoted patterns.
+
+> The use in the previous iteration of `{{` and `}}` surrounding code-mode messages was identified as a potential negative, 
+> as the closing `}}` are superfluous to the message.
+
+The use of `>>` to represent the "starting code-mode sigil" is **_not_** final.
+**_Do not fixate on the specific character sequence when choosing (or not) this design._**
+
+**Examples**
+```
+Hello world!
+```
+```
+Hello {$user}
+```
+```
+>>input {$user :function option=value}
+{Hello {$user}}
+
+>>input {$user :function option=value}{Hello {$user}}
+```
+```
+>>input {$var :function option=value}
+local $foo = {$bar :function option=value}
+{Hello {$var}, you have a {$foo}}
+
+>>input {$var :function option=value}local $foo = {$bar :function option=value}{Hello {$var}, you have a {$foo}}
+```
+```
+>>match {$foo} {$bar}
+when foo bar {Hello {$foo} you have a {$var}}
+when * * {{$foo} hello you have a {$var}}
+
+>>match {$foo}{$bar}when foo bar {Hello {$foo} you have a {$var}}when * * {{$foo} hello you have a {$var}}
+```
+
+```
+>>match {$foo :function option=value} {$bar :function option=value}
+when a b {  {$foo} is {$bar}  }
+when x y {  {$foo} is {$bar}  }
+when * * {  {$foo} is {$bar}  }
+
+>>match {$foo :function option=value} {$bar :function option=value}when a b {  {$foo} is {$bar}  }when x y {  {$foo} is {$bar}  }when * * {  {$foo} is {$bar}  }
+```
+
+### Candidate 3a
+
+**Description:** Use sigils for code mode, use `{`/`}` for keys
+
+- Starts in text mode. 
+- Uses a sigil for code statements. 
+  - Requires the code-mode sigil to be escaped in **_unquoted_** patterns.
+  - Quoted patterns do not require this sigil to be escaped.
+  - Note that decisions about auto-trimming affect the escaping situation. 
+    If quoting the pattern is required, no additional escapes are needed.
+- Placeholders and expressions use `{`/`}`:
+  > `{$var}`, `{unquoted}`, `{|quoted|}`, `{$var :function}`
+
+The use of `~` as the sigil is **_not_** an inherent part of the design here.
+The actual sigil or sigil sequence needs to be decided. 
+Note that using a doubled-sigil reduces the need for escaping.
+
+Patterns in this syntax are generally unquoted,
+but MAY be quoted with the 2023-10-09 consensus `{{`/`}}` quotes.
+
+Patterns lacking declarations, selectors, or both, are **_not_** auto-trimmed.
+Whitespace in quoted patterns is significant.
+Whitespace in unquoted patterns may or may not be significant (hot topic).
+
+```
+Hello world!
+```
+```
+Hello {$user}!
+```
+```
+~input {$var :function option=value}
+Hello {$var}
+
+~input {$var :function option=value}Hello {$var}
+```
+```
+~input {$var :function option=value}
+~local $foo = {$bar :function option=value}
+Hello {$var}, you have a {$foo}
+
+~input {$var :function option=value}~local $foo = {$bar :function option=value}Hello {$var}, you have a {$foo}
+```
+```
+~match {$foo} {$bar}
+~when{foo bar} Hello {$foo} you have a {$var}
+~when{  *   *} {$foo} hello you have a {$var}
+
+~match {$foo}{$bar}~when{foo bar} Hello {$foo} you have a {$var}~when{* *} {$foo} hello you have a {$var}
+```
+
+```
+~match {$foo :function option=value} {$bar :function option=value}
+~when {a b} {{  {$foo} is {$bar}  }}
+~when {x y} {||}  {$foo} is {$bar}  {||}
+~when {* *} {|  |}{$foo} is {$bar}{|  |}
+
+~match {$foo :function option=value}{$bar :function option=value}~when {a b}{{  {$foo} is {$bar}  }}~when {x y} {||}{$foo} is {$bar}  {||}~when {* *}{|  |}{$foo} is {$bar}{|  |}
+```

From 0d44ddf74a6698f30b8e902db927d1cbaacd2ef9 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 12:59:34 -0700
Subject: [PATCH 02/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Eemeli Aro <eemeli@mozilla.com>
---
 exploration/syntax-exploration-2.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index e06be24c20..beac029374 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -65,7 +65,7 @@ Hello {$var}, you have a {$foo}
 {#when x y} {{  {$foo} is {$bar}  }}
 {#when * *} {|  |}{$foo} is {$bar}{|  |}
 
-{#match {$foo :function option=value} {$bar :function option=value}}{#when a b} {{  {$foo} is {$bar}  }}{#when x y} {{  {$foo} is {$bar}  }}{#when * *} {|  |}{$foo} is {$bar}{|  |}
+{#match {$foo :function option=value}{$bar :function option=value}}{#when a b}{{  {$foo} is {$bar}  }}{#when x y}{{  {$foo} is {$bar}  }}{#when * *}{|  |}{$foo} is {$bar}{|  |}
 ```
 
 ### Candidate 2a

From cbdefb6319232c82c5987a1c033ce5eb12f8eddf Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 12:59:45 -0700
Subject: [PATCH 03/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Eemeli Aro <eemeli@mozilla.com>
---
 exploration/syntax-exploration-2.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index beac029374..8a7b44f460 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -107,11 +107,11 @@ local $foo = {$bar :function option=value}
 >>input {$var :function option=value}local $foo = {$bar :function option=value}{Hello {$var}, you have a {$foo}}
 ```
 ```
->>match {$foo} {$bar}
-when foo bar {Hello {$foo} you have a {$var}}
-when * * {{$foo} hello you have a {$var}}
+>>match {$foo}
+when foo {Hello {$foo} you have a {$var}}
+when * {{$foo} hello you have a {$var}}
 
->>match {$foo}{$bar}when foo bar {Hello {$foo} you have a {$var}}when * * {{$foo} hello you have a {$var}}
+>>match {$foo}when foo{Hello {$foo} you have a {$var}}when *{{$foo} hello you have a {$var}}
 ```
 
 ```

From 2d208a28c76dea454a9cc9f2e2e6d6547f09977d Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 12:59:51 -0700
Subject: [PATCH 04/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Eemeli Aro <eemeli@mozilla.com>
---
 exploration/syntax-exploration-2.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 8a7b44f460..008c74633e 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -53,11 +53,11 @@ Hello {$var}, you have a {$foo}
 {#input $var :function option=value}{#local $foo = $bar :function option=value}Hello {$var}, you have a {$foo}
 ```
 ```
-{#match {$foo} {$bar}}
-{#when foo bar} Hello {$foo} you have a {$var}
-{#when * *} {$foo} hello you have a {$var}
+{#match {$foo}}
+{#when foo} Hello {$foo} you have a {$var}
+{#when *} {$foo} hello you have a {$var}
 
-{#match {$foo} {$bar}}{#when foo bar}Hello {$foo} you have a {$var}{#when * *}{$foo} hello you have a {$var}
+{#match {$foo}}{#when foo}Hello {$foo} you have a {$var}{#when *}{$foo} hello you have a {$var}
 ```
 ```
 {#match {$foo :function option=value} {$bar :function option=value}}

From 534f31fff1282d0dc1ce5faa5356526cac50ec24 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 13:00:04 -0700
Subject: [PATCH 05/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Eemeli Aro <eemeli@mozilla.com>
---
 exploration/syntax-exploration-2.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 008c74633e..bfc55dc8f9 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -120,7 +120,7 @@ when a b {  {$foo} is {$bar}  }
 when x y {  {$foo} is {$bar}  }
 when * * {  {$foo} is {$bar}  }
 
->>match {$foo :function option=value} {$bar :function option=value}when a b {  {$foo} is {$bar}  }when x y {  {$foo} is {$bar}  }when * * {  {$foo} is {$bar}  }
+>>match {$foo :function option=value}{$bar :function option=value}when a b{  {$foo} is {$bar}  }when x y{  {$foo} is {$bar}  }when * *{  {$foo} is {$bar}  }
 ```
 
 ### Candidate 3a

From d3d65c755ce40521ae793518fa2d333cb3ea7d75 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 13:02:24 -0700
Subject: [PATCH 06/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Eemeli Aro <eemeli@mozilla.com>
---
 exploration/syntax-exploration-2.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index bfc55dc8f9..46a25a80b4 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -136,7 +136,7 @@ when * * {  {$foo} is {$bar}  }
 - Placeholders and expressions use `{`/`}`:
   > `{$var}`, `{unquoted}`, `{|quoted|}`, `{$var :function}`
 
-The use of `~` as the sigil is **_not_** an inherent part of the design here.
+The use of `%` as the sigil is **_not_** an inherent part of the design here.
 The actual sigil or sigil sequence needs to be decided. 
 Note that using a doubled-sigil reduces the need for escaping.
 

From 7c58a86c98f69db9e4477f723316324ed5d50247 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 13:02:29 -0700
Subject: [PATCH 07/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Eemeli Aro <eemeli@mozilla.com>
---
 exploration/syntax-exploration-2.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 46a25a80b4..c4011de03c 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -154,10 +154,10 @@ Hello world!
 Hello {$user}!
 ```
 ```
-~input {$var :function option=value}
+%input {$var :function option=value}
 Hello {$var}
 
-~input {$var :function option=value}Hello {$var}
+%input {$var :function option=value}Hello {$var}
 ```
 ```
 ~input {$var :function option=value}

From 292e8df25ca6712cf0fbc58de336f6edf4abfccd Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 13:02:36 -0700
Subject: [PATCH 08/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Eemeli Aro <eemeli@mozilla.com>
---
 exploration/syntax-exploration-2.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index c4011de03c..c7f28eb54c 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -160,11 +160,11 @@ Hello {$var}
 %input {$var :function option=value}Hello {$var}
 ```
 ```
-~input {$var :function option=value}
-~local $foo = {$bar :function option=value}
+%input {$var :function option=value}
+%local $foo = {$bar :function option=value}
 Hello {$var}, you have a {$foo}
 
-~input {$var :function option=value}~local $foo = {$bar :function option=value}Hello {$var}, you have a {$foo}
+%input {$var :function option=value}%local $foo = {$bar :function option=value}Hello {$var}, you have a {$foo}
 ```
 ```
 ~match {$foo} {$bar}

From 01075b43ec6baa003a779682b6da7fa0e6bead16 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 13:03:12 -0700
Subject: [PATCH 09/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Eemeli Aro <eemeli@mozilla.com>
---
 exploration/syntax-exploration-2.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index c7f28eb54c..cf19d7193b 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -167,11 +167,11 @@ Hello {$var}, you have a {$foo}
 %input {$var :function option=value}%local $foo = {$bar :function option=value}Hello {$var}, you have a {$foo}
 ```
 ```
-~match {$foo} {$bar}
-~when{foo bar} Hello {$foo} you have a {$var}
-~when{  *   *} {$foo} hello you have a {$var}
+%match {$foo}
+%when{foo} Hello {$foo} you have a {$var}
+%when{*} {$foo} hello you have a {$var}
 
-~match {$foo}{$bar}~when{foo bar} Hello {$foo} you have a {$var}~when{* *} {$foo} hello you have a {$var}
+%match {$foo}%when{foo}Hello {$foo} you have a {$var}%when{*}{$foo} hello you have a {$var}
 ```
 
 ```

From 41a841c8b9009cd220f380fa2861f38a344429fb Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 13:03:18 -0700
Subject: [PATCH 10/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Eemeli Aro <eemeli@mozilla.com>
---
 exploration/syntax-exploration-2.md | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index cf19d7193b..56968c920b 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -175,10 +175,10 @@ Hello {$var}, you have a {$foo}
 ```
 
 ```
-~match {$foo :function option=value} {$bar :function option=value}
-~when {a b} {{  {$foo} is {$bar}  }}
-~when {x y} {||}  {$foo} is {$bar}  {||}
-~when {* *} {|  |}{$foo} is {$bar}{|  |}
+%match {$foo :function option=value} {$bar :function option=value}
+%when {a b} {{  {$foo} is {$bar}  }}
+%when {x y} {||}  {$foo} is {$bar}  {||}
+%when {* *} {|  |}{$foo} is {$bar}{|  |}
 
-~match {$foo :function option=value}{$bar :function option=value}~when {a b}{{  {$foo} is {$bar}  }}~when {x y} {||}{$foo} is {$bar}  {||}~when {* *}{|  |}{$foo} is {$bar}{|  |}
+%match {$foo :function option=value}{$bar :function option=value}%when {a b}{{  {$foo} is {$bar}  }}%when {x y} {||}{$foo} is {$bar}  {||}%when {* *}{|  |}{$foo} is {$bar}{|  |}
 ```

From 2f7517b7cfd70a6916dc387209bcd5f8aa9003dd Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 13:39:34 -0700
Subject: [PATCH 11/22] Add comparison matrix (first draft) and sigils section

---
 exploration/syntax-exploration-2.md | 30 ++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 56968c920b..7b2615c15d 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -9,7 +9,11 @@ We have generally used `#` as the placeholder for this sigil in the previous ite
 
 ## Comparison Matrix
 
-... goes here...
+| Option | Description                                                    | Doesn’t Nest {} | Doesn’t Need More Escapes | Doesn’t Require Quoted Pattern |  Counted {} works | Multiple Expression Syntaxes |
+| :----- | :------------------------------------------------------------- | :-------------- | :------------------------ | :----------------------------- |  :--------------- | :------------ |
+| 1a     | Invert for text mode, distinguish statements from placeholders | -               | +                         | +                              | +                | - |
+| 2a     | Text first, current syntax for complex messages                | -               | +                         | -                              | -                | + |
+| 3a     | Use sigils for code mode, use `{`/`}` for keys                 | +               | -                         | +                              | +                | + |
 
 ## Candidates
 
@@ -182,3 +186,27 @@ Hello {$var}, you have a {$foo}
 
 %match {$foo :function option=value}{$bar :function option=value}%when {a b}{{  {$foo} is {$bar}  }}%when {x y} {||}{$foo} is {$bar}  {||}%when {* *}{|  |}{$foo} is {$bar}{|  |}
 ```
+
+
+## Sigil Candidates
+
+Some of the above syntaxes require an additional sigil.
+
+Here are the potential sigils that can be used:
+
+| Sigil | Positives | Negatives |
+|---|---|---|
+| `!` |  | Means "not" in most programming languages. |
+| `@` | Feels like code? | Means "address" in a lot of contexts. Might be used for annotations |
+| `#` | Feels like code. Similar to `#define`. | Common in real text. Used for _everything_ |
+| `%` | Feels like code. Used by some templating languages. | Common in real text. |
+| `^` |  | Uncommon choice. Harder to see. |
+| `&` |  | Used in a lot of escapes, notably HTML. |
+| `+` |  | Looks like an operator. |
+| `_` | Feels like code. | Looks like a name prefix. Hard to see. |
+| `\|` |  | Already used in our syntax for a diff purpose. Weird. |
+| `>` |  | Has meaning in markup. Wants to pair with `<`. |
+| `<` |  | Has meaning in markup. Wants to pair with `>`. |
+| '?' |  | Looks like `?` operator. Looks like a variable. Very common in real text. |
+| '::' |  | Common in real text. Looks like part of a ternary operator. |
+| ';' | Can't think of any. | Looks like a statement close. |

From da4ea08dd2cba440e05269a1e6018308e6caaa06 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 14:55:42 -0700
Subject: [PATCH 12/22] Fix typos

---
 exploration/syntax-exploration-2.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 7b2615c15d..31d0e9c8e1 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -207,6 +207,6 @@ Here are the potential sigils that can be used:
 | `\|` |  | Already used in our syntax for a diff purpose. Weird. |
 | `>` |  | Has meaning in markup. Wants to pair with `<`. |
 | `<` |  | Has meaning in markup. Wants to pair with `>`. |
-| '?' |  | Looks like `?` operator. Looks like a variable. Very common in real text. |
-| '::' |  | Common in real text. Looks like part of a ternary operator. |
-| ';' | Can't think of any. | Looks like a statement close. |
+| `?` |  | Looks like `?` operator. Looks like a variable. Very common in real text. |
+| `::` |  | Common in real text. Looks like part of a ternary operator. |
+| `;` | Can't think of any. | Looks like a statement close. |

From 57aa00825761ab7bd3ab814f3da4ce8563c1977b Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Mon, 16 Oct 2023 15:01:57 -0700
Subject: [PATCH 13/22] Flesh out sigils to make complete.

---
 exploration/syntax-exploration-2.md | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 31d0e9c8e1..1bb1d746bc 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -210,3 +210,14 @@ Here are the potential sigils that can be used:
 | `?` |  | Looks like `?` operator. Looks like a variable. Very common in real text. |
 | `::` |  | Common in real text. Looks like part of a ternary operator. |
 | `;` | Can't think of any. | Looks like a statement close. |
+| `~` |  | Looks like an operator. |
+| `*` |  | Looks like a wildcard. Already used by the syntax. |
+| `-` |  | Too common in normal text. |
+| `=` |  | Looks like an operator. Already used by the syntax. |
+| `[` |  | Enclosing punctuation. |
+| `]` |  | Enclosing punctuation. |
+| `.` |  | Too common in normal text. Used by other syntaxes |
+| `,` |  | Too common in normal text. Not code-like? |
+| `\`` |  | Quote mark. |
+| `'`  |  | Quote mark. |
+| `"` |  | Quote mark. |

From c27c0e25f945624d3b3e8b959a7fe29e38c21e33 Mon Sep 17 00:00:00 2001
From: Eemeli Aro <eemeli@mozilla.com>
Date: Tue, 17 Oct 2023 12:03:02 +0300
Subject: [PATCH 14/22] Update sigil table, adding \

---
 exploration/syntax-exploration-2.md | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 1bb1d746bc..c9501ce6db 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -198,13 +198,14 @@ Here are the potential sigils that can be used:
 |---|---|---|
 | `!` |  | Means "not" in most programming languages. |
 | `@` | Feels like code? | Means "address" in a lot of contexts. Might be used for annotations |
-| `#` | Feels like code. Similar to `#define`. | Common in real text. Used for _everything_ |
+| `#` | Feels like code. Similar to `#define`. | Common in real text. Used for _everything_, in particular comments. |
 | `%` | Feels like code. Used by some templating languages. | Common in real text. |
 | `^` |  | Uncommon choice. Harder to see. |
 | `&` |  | Used in a lot of escapes, notably HTML. |
 | `+` |  | Looks like an operator. |
 | `_` | Feels like code. | Looks like a name prefix. Hard to see. |
 | `\|` |  | Already used in our syntax for a diff purpose. Weird. |
+| `\` | Feels like code. Already escaped in patterns. | May beed doubling in a resource format. |
 | `>` |  | Has meaning in markup. Wants to pair with `<`. |
 | `<` |  | Has meaning in markup. Wants to pair with `>`. |
 | `?` |  | Looks like `?` operator. Looks like a variable. Very common in real text. |
@@ -218,6 +219,6 @@ Here are the potential sigils that can be used:
 | `]` |  | Enclosing punctuation. |
 | `.` |  | Too common in normal text. Used by other syntaxes |
 | `,` |  | Too common in normal text. Not code-like? |
-| `\`` |  | Quote mark. |
+| <code>`</code> |  | Quote mark. |
 | `'`  |  | Quote mark. |
 | `"` |  | Quote mark. |

From b7a74ec462efe007270c90de940044d51aacae42 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Tue, 17 Oct 2023 07:30:24 -0700
Subject: [PATCH 15/22] Update exploration/syntax-exploration-2.md

---
 exploration/syntax-exploration-2.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index c9501ce6db..7c7df80501 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -205,7 +205,7 @@ Here are the potential sigils that can be used:
 | `+` |  | Looks like an operator. |
 | `_` | Feels like code. | Looks like a name prefix. Hard to see. |
 | `\|` |  | Already used in our syntax for a diff purpose. Weird. |
-| `\` | Feels like code. Already escaped in patterns. | May beed doubling in a resource format. |
+| `\` | Feels like code. Already escaped in patterns. | May require escaping (doubling) in host formats. |
 | `>` |  | Has meaning in markup. Wants to pair with `<`. |
 | `<` |  | Has meaning in markup. Wants to pair with `>`. |
 | `?` |  | Looks like `?` operator. Looks like a variable. Very common in real text. |

From 9c00f18852c4e48e384913cb2cd891168fc407f3 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Tue, 17 Oct 2023 07:49:49 -0700
Subject: [PATCH 16/22] Add section about sigiling and whitespace

---
 exploration/syntax-exploration-2.md | 32 +++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 7c7df80501..366f186098 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -187,6 +187,38 @@ Hello {$var}, you have a {$foo}
 %match {$foo :function option=value}{$bar :function option=value}%when {a b}{{  {$foo} is {$bar}  }}%when {x y} {||}{$foo} is {$bar}  {||}%when {* *}{|  |}{$foo} is {$bar}{|  |}
 ```
 
+## Whitespace and Pattern Boundaries
+
+One key consideration for the above options is distinguishing the boundary between 
+the end of a _pattern_ and the start of a _variant_ (`when` clause).
+This was not an issue in the code-mode syntax because the patterns were always delimited ("quoted").
+
+> [*Note]
+> This type of syntax is only needed if patterns are not quoted.
+> The "hot debate" in our 2023-10-16 teleconference was between "WYSIWYG"
+> no-whitespace-trimming supporters and current WG consensus.
+> For current consensus and discussion of whitespace design see [here](pattern-exterior-whitespace.md)
+
+- Candidate 1a uses a double sigil `{#` or distinguishing sequence `{#when` to accomplish this.
+- Candidate 2a quotes all patterns in code-mode.
+- Candidate 3a uses a sigil-keyword sequence `%when` that required at least some additional escaping.
+
+It is reasonable to think that we might modify this particular part of the syntax
+to improve usability. **_Keep in mind the need for single-line authoring._**
+
+For example:
+
+>```
+>%match {$foo}
+>%%{0} You have no ducks.
+>%%{one} You have {$foo} duck.
+>%%{*} You have {$foo} ducks.
+>
+>%match {$foo}
+>[[0]] You have no ducks.
+>[[one]] You have {$foo} duck.
+>[[*]] You have {$foo} duck.
+>```
 
 ## Sigil Candidates
 

From 8ec13f3350b04d954c299a1a11331b664aa7662a Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Tue, 17 Oct 2023 13:28:06 -0700
Subject: [PATCH 17/22] Changes to 3a based on slack conversation threads

---
 exploration/syntax-exploration-2.md | 31 +++++++++++++++--------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 366f186098..c871ddd2d5 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -13,7 +13,7 @@ We have generally used `#` as the placeholder for this sigil in the previous ite
 | :----- | :------------------------------------------------------------- | :-------------- | :------------------------ | :----------------------------- |  :--------------- | :------------ |
 | 1a     | Invert for text mode, distinguish statements from placeholders | -               | +                         | +                              | +                | - |
 | 2a     | Text first, current syntax for complex messages                | -               | +                         | -                              | -                | + |
-| 3a     | Use sigils for code mode, use `{`/`}` for keys                 | +               | -                         | +                              | +                | + |
+| 3a     | Use sigils for code mode                                       | +               | -                         | +                              | +                | + |
 
 ## Candidates
 
@@ -129,7 +129,7 @@ when * * {  {$foo} is {$bar}  }
 
 ### Candidate 3a
 
-**Description:** Use sigils for code mode, use `{`/`}` for keys
+**Description:** Use sigils for code mode
 
 - Starts in text mode. 
 - Uses a sigil for code statements. 
@@ -137,12 +137,13 @@ when * * {  {$foo} is {$bar}  }
   - Quoted patterns do not require this sigil to be escaped.
   - Note that decisions about auto-trimming affect the escaping situation. 
     If quoting the pattern is required, no additional escapes are needed.
-- Placeholders and expressions use `{`/`}`:
+- Expressions use `{`/`}`:
   > `{$var}`, `{unquoted}`, `{|quoted|}`, `{$var :function}`
-
-The use of `%` as the sigil is **_not_** an inherent part of the design here.
-The actual sigil or sigil sequence needs to be decided. 
-Note that using a doubled-sigil reduces the need for escaping.
+  - There is only one expression syntax, which applies to all expressions.
+  - Note: placeholders are expressions.
+- Variants use a double-sigil `%[` at the start and close the list of `keys`
+  with a `]`.
+  - The sequence `%[` must be escaped in unquoted patterns.
 
 Patterns in this syntax are generally unquoted,
 but MAY be quoted with the 2023-10-09 consensus `{{`/`}}` quotes.
@@ -172,19 +173,19 @@ Hello {$var}, you have a {$foo}
 ```
 ```
 %match {$foo}
-%when{foo} Hello {$foo} you have a {$var}
-%when{*} {$foo} hello you have a {$var}
+%[foo] Hello {$foo} you have a {$var}
+%[*] {$foo} hello you have a {$var}
 
-%match {$foo}%when{foo}Hello {$foo} you have a {$var}%when{*}{$foo} hello you have a {$var}
+%match {$foo}%[foo] Hello {$foo} you have a {$var}%[*] {$foo} hello you have a {$var}
 ```
 
 ```
 %match {$foo :function option=value} {$bar :function option=value}
-%when {a b} {{  {$foo} is {$bar}  }}
-%when {x y} {||}  {$foo} is {$bar}  {||}
-%when {* *} {|  |}{$foo} is {$bar}{|  |}
+%[a b] {{  {$foo} is {$bar}  }}
+%[x y] {||}  {$foo} is {$bar}  {||}
+%[* *] {|  |}{$foo} is {$bar}{|  |}
 
-%match {$foo :function option=value}{$bar :function option=value}%when {a b}{{  {$foo} is {$bar}  }}%when {x y} {||}{$foo} is {$bar}  {||}%when {* *}{|  |}{$foo} is {$bar}{|  |}
+%match {$foo :function option=value} {$bar :function option=value}%[a b] {{  {$foo} is {$bar}  }}%[x y] {||}  {$foo} is {$bar}  {||}%[* *] {|  |}{$foo} is {$bar}{|  |}
 ```
 
 ## Whitespace and Pattern Boundaries
@@ -201,7 +202,7 @@ This was not an issue in the code-mode syntax because the patterns were always d
 
 - Candidate 1a uses a double sigil `{#` or distinguishing sequence `{#when` to accomplish this.
 - Candidate 2a quotes all patterns in code-mode.
-- Candidate 3a uses a sigil-keyword sequence `%when` that required at least some additional escaping.
+- Candidate 3a uses a sigil sequence `%[` to accomplish this
 
 It is reasonable to think that we might modify this particular part of the syntax
 to improve usability. **_Keep in mind the need for single-line authoring._**

From afeea3fa75da08ae4f21fc95e1a7fa3dda18c521 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Wed, 18 Oct 2023 08:43:48 -0700
Subject: [PATCH 18/22] Change comparison table to be more neutral about
 unquoted pattern

---
 exploration/syntax-exploration-2.md | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index c871ddd2d5..385ef7349c 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -9,12 +9,16 @@ We have generally used `#` as the placeholder for this sigil in the previous ite
 
 ## Comparison Matrix
 
-| Option | Description                                                    | Doesn’t Nest {} | Doesn’t Need More Escapes | Doesn’t Require Quoted Pattern |  Counted {} works | Multiple Expression Syntaxes |
+> [!Note]
+> The `+` and `-` values do not connote a value judgment about a given candidate.
+
+| Option | Description                                                    | Doesn’t Nest {} | Doesn’t Need More Escapes | Allows Unquoted Pattern |  Counted {} works | Multiple Expression Syntaxes |
 | :----- | :------------------------------------------------------------- | :-------------- | :------------------------ | :----------------------------- |  :--------------- | :------------ |
 | 1a     | Invert for text mode, distinguish statements from placeholders | -               | +                         | +                              | +                | - |
 | 2a     | Text first, current syntax for complex messages                | -               | +                         | -                              | -                | + |
 | 3a     | Use sigils for code mode                                       | +               | -                         | +                              | +                | + |
 
+
 ## Candidates
 
 ### Candidate 1a

From 27565fdfcc697477100549a3665cec141fed57a0 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Wed, 18 Oct 2023 12:50:55 -0700
Subject: [PATCH 19/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Elango Cheran <elango@unicode.org>
---
 exploration/syntax-exploration-2.md | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 385ef7349c..6f58b79ffa 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -88,10 +88,7 @@ Starts in text mode, but switches to the current "code-mode" syntax for any mess
   Note that "pattern whitespace" is only that whitespace that appears inside the quoting `{`/`}`
   for quoted patterns.
 
-> The use in the previous iteration of `{{` and `}}` surrounding code-mode messages was identified as a potential negative, 
-> as the closing `}}` are superfluous to the message.
-
-The use of `>>` to represent the "starting code-mode sigil" is **_not_** final.
+The use of `{# ... #}` to represent the starting and ending code-mode sigils is **_not_** final.
 **_Do not fixate on the specific character sequence when choosing (or not) this design._**
 
 **Examples**

From 2207a631911487a3e263fa00867677d8535fdfc2 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Wed, 18 Oct 2023 12:51:16 -0700
Subject: [PATCH 20/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Elango Cheran <elango@unicode.org>
---
 exploration/syntax-exploration-2.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index 6f58b79ffa..ef81e1b50e 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -99,8 +99,10 @@ Hello world!
 Hello {$user}
 ```
 ```
->>input {$user :function option=value}
+{#
+input {$user :function option=value}
 {Hello {$user}}
+#}
 
 >>input {$user :function option=value}{Hello {$user}}
 ```

From 6315c303a276caa2073513952160312735916ebf Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Wed, 18 Oct 2023 12:51:28 -0700
Subject: [PATCH 21/22] Update exploration/syntax-exploration-2.md

Co-authored-by: Elango Cheran <elango@unicode.org>
---
 exploration/syntax-exploration-2.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index ef81e1b50e..fb0b015a85 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -104,7 +104,7 @@ input {$user :function option=value}
 {Hello {$user}}
 #}
 
->>input {$user :function option=value}{Hello {$user}}
+{#input {$user :function option=value}{Hello {$user}}#}
 ```
 ```
 >>input {$var :function option=value}

From 74e610b307856a802eab0f551e8851633e934031 Mon Sep 17 00:00:00 2001
From: Addison Phillips <addison@unicode.org>
Date: Wed, 18 Oct 2023 12:52:27 -0700
Subject: [PATCH 22/22] Apply suggestions from code review

Co-authored-by: Elango Cheran <elango@unicode.org>
---
 exploration/syntax-exploration-2.md | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/exploration/syntax-exploration-2.md b/exploration/syntax-exploration-2.md
index fb0b015a85..7147bf3e4b 100644
--- a/exploration/syntax-exploration-2.md
+++ b/exploration/syntax-exploration-2.md
@@ -107,27 +107,33 @@ input {$user :function option=value}
 {#input {$user :function option=value}{Hello {$user}}#}
 ```
 ```
->>input {$var :function option=value}
+{#
+input {$var :function option=value}
 local $foo = {$bar :function option=value}
 {Hello {$var}, you have a {$foo}}
+#}
 
->>input {$var :function option=value}local $foo = {$bar :function option=value}{Hello {$var}, you have a {$foo}}
+{#input {$var :function option=value}local $foo = {$bar :function option=value}{Hello {$var}, you have a {$foo}}#}
 ```
 ```
->>match {$foo}
+{#
+match {$foo}
 when foo {Hello {$foo} you have a {$var}}
 when * {{$foo} hello you have a {$var}}
+#}
 
->>match {$foo}when foo{Hello {$foo} you have a {$var}}when *{{$foo} hello you have a {$var}}
+{#match {$foo}when foo{Hello {$foo} you have a {$var}}when *{{$foo} hello you have a {$var}}#}
 ```
 
 ```
->>match {$foo :function option=value} {$bar :function option=value}
+{#
+match {$foo :function option=value} {$bar :function option=value}
 when a b {  {$foo} is {$bar}  }
 when x y {  {$foo} is {$bar}  }
 when * * {  {$foo} is {$bar}  }
+#}
 
->>match {$foo :function option=value}{$bar :function option=value}when a b{  {$foo} is {$bar}  }when x y{  {$foo} is {$bar}  }when * *{  {$foo} is {$bar}  }
+{#match {$foo :function option=value}{$bar :function option=value}when a b{  {$foo} is {$bar}  }when x y{  {$foo} is {$bar}  }when * *{  {$foo} is {$bar}  }#}
 ```
 
 ### Candidate 3a