Add ;:? to keybar and help

5 files changed, 60 insertions, 2 deletions

diff --git a/help/README.md b/help/README.md
index 0571a25b..011d7459 100644
--- a/help/README.md
+++ b/help/README.md
@@ -47,6 +47,7 @@ Symbols are listed in alphabetical order of page name, ignoring syntactical role
 | `⍋` | [Grade Up, Bins Up](gradeup_binsup.md) |
 | `≥` | [Greater Than or Equal To](greaterthanorequalto.md) |
 | `⊔` | [Group Indices, Group](groupindices_group.md) |
+| `:` | [Header](header.md) |
 | `⊣` | [Identity, Left](identity_left.md) |
 | `⊢` | [Identity, Right](identity_right.md) |
 | `/` | [Indices, Replicate](indices_replicate.md) |
@@ -62,12 +63,14 @@ Symbols are listed in alphabetical order of page name, ignoring syntactical role
 | `𝔽` | [Modifier Left operand](modifierleftoperand.md) |
 | `.` | [Namespace Field](namespacefield.md) |
 | `-` | [Negate, Subtract](negate_subtract.md) |
+| `;` | [Next Body](nextbody.md) |
 | `·` | [Nothing](nothing.md) |
 | `¬` | [Logical Not, Span](not_span.md) |
 | `@` | [Null Character](nullcharacter.md) |
 | `⊒` | [Occurrence Count, Progressive Index Of](occurrencecount_progressiveindexof.md) |
 | `○` | [Atop, Over](over.md) |
 | `π` | [Pi](pi.md) |
+| `?` | [Predicate](predicate.md) |
 | `↑` | [Prefixes, Take](prefixes_take.md) |
 | `↕` | [Range, Windows](range_windows.md) |
 | `=` | [Rank, Equal To](rank_equals.md) |
diff --git a/help/genhelp.bqn b/help/genhelp.bqn
index 2cdfe2b6..4bf27e09 100755
--- a/help/genhelp.bqn
+++ b/help/genhelp.bqn
@@ -1,13 +1,16 @@
 #!/usr/bin/env bqn
 
+files ← "README.md"⊸≢¨⊸/ (⍋(¬∊⟜"_.")⊸/¨)⊸⊏ ".md"⊸(-∘≠⊸↑≡⊣)¨⊸/ •file.List ""
+
 thing ← {
     data ← •FLines 𝕩
-    names ← (⊣∾", "∾⊢)´{(¬·∧`' '⊸=)⊸/⌾⌽(2+⊑/':'=𝕩)↓𝕩}¨("## "≡3⊸↑)¨⊸/data
+    names ← (⊣∾", "∾⊢)´{(¬·∧`' '⊸=)⊸/⌾⌽(»·∧`⌾⌽':'⊸≠)⊸/𝕩}¨("## "≡3⊸↑)¨⊸/data
     t‿d ←  ∾/¨(⊏data)=¨"()"
     sym ← (+`·»⊸-˝(¬»∧«)∘=⟜'`'∧⎉1"()"=⌜⊢)⊸/ 2⊑data
     sym (1+'|'⊸=)⊸(/+(-´"\|")×{«⊒/𝕨})↩
+    sym "`,` or `⋄`"⍟("`,``⋄`"⊸≡)↩
     "| " ∾ sym ∾ " | [" ∾ names ∾ "]("∾𝕩∾ ") |"
-}¨•args(¬∘∊/⊣)⟨"README.md"⟩
+}¨ files
 
 head ← ⟨
 "*View this file with results and syntax highlighting [here](https://mlochbaum.github.io/BQN/help/index.html).*"
diff --git a/help/header.md b/help/header.md
new file mode 100644
index 00000000..c881943a
--- /dev/null
+++ b/help/header.md
@@ -0,0 +1,20 @@
+*View this file with results and syntax highlighting [here](https://mlochbaum.github.io/BQN/help/header.html).*
+
+# Colon (`:`)
+
+## `:`: Header
+[→full documentation](../doc/block.md#block-headers)
+
+Placed at the end of a block header. A header has syntax that matches the way the block is called. It indicates the block type, and number and structure of inputs.
+
+        "xy" {a‿b _op c: b} ∞
+
+Multiple bodies are searched in order to find one with a matching header.
+
+        F ← {m Fn n: m+Fn n;  𝕊n: 2×n;  𝕊⁼𝕩: 𝕩÷2}
+
+        F 3      # 𝕊n
+
+        F⁼ 6     # 𝕊⁼𝕩
+
+        10 F 3   # m Fn n
diff --git a/help/nextbody.md b/help/nextbody.md
new file mode 100644
index 00000000..02cc710c
--- /dev/null
+++ b/help/nextbody.md
@@ -0,0 +1,16 @@
+*View this file with results and syntax highlighting [here](https://mlochbaum.github.io/BQN/help/nextbody.html).*
+
+# Semicolon (`;`)
+
+## `;`: Next Body
+[→full documentation](../doc/block.md#multiple-bodies)
+
+End the current block body and start a new one. [Headers](header.md) (`:`) and [predicates](predicate.md) (`?`) can control which body is evaluated. A function can have two headers without these, indicating the monadic and dyadic cases.
+
+        3 { 𝕩÷2 ; -𝕨‿𝕩 } 4   # Monadic and dyadic cases
+
+        F ← {𝕊a‿b: a-b; 𝕊a‿b‿c: b+c}
+
+        F 5‿2                # Matches first header
+
+        F 1‿3‿6              # Matches second header
diff --git a/help/predicate.md b/help/predicate.md
new file mode 100644
index 00000000..eefd390a
--- /dev/null
+++ b/help/predicate.md
@@ -0,0 +1,16 @@
+*View this file with results and syntax highlighting [here](https://mlochbaum.github.io/BQN/help/predicate.html).*
+
+# Question Mark (`?`)
+
+## `?`: Predicate
+[→full documentation](../doc/block.md#predicates)
+
+Follows a statement in a block, which must return 0 or 1. If it's 0, stop the current body and evaluate the next eligible one instead. Variables defined before the `?` stay if execution continues (1) but don't carry over to other bodies (0).
+
+        {0 ? 3 ; 4}
+
+        Min ← {𝕨<𝕩 ? 𝕨 ; 𝕩}
+
+        3 Min 5
+
+        4 Min 2