From 16ea00650607ba5affc3b94fe133e69920954aa5 Mon Sep 17 00:00:00 2001
From: Marshall Lochbaum <mwlochbaum@gmail.com>
Date: Wed, 1 Jun 2022 17:20:29 -0400
Subject: Use ; for block valences in reference.bqn where reasonable

---
 spec/primitive.md  | 4 +---
 spec/reference.bqn | 8 ++++----
 2 files changed, 5 insertions(+), 7 deletions(-)

(limited to 'spec')

diff --git a/spec/primitive.md b/spec/primitive.md
index 8f40fa85..ef3055c4 100644
--- a/spec/primitive.md
+++ b/spec/primitive.md
@@ -89,7 +89,7 @@ There's little to say about BQN's true combinators, since each is simply a patte
 
 - **Choose** (`◶`) is later redefined to use the complete `⊑` rather than the simple version assumed (using this primitive means it's not a true combinator).
 - **Constant** (`˙`)
-- **Valences** (`⊘`) uses a trick with ambivalent `-` to find out whether there's a left argument, described below.
+- **Valences** (`⊘`)
 - **Right** (`⊢`)
 - **Left** (`⊣`)
 - **Self**/**Swap** (`˜`)
@@ -98,8 +98,6 @@ There's little to say about BQN's true combinators, since each is simply a patte
 - **Before**/**Bind** (`⊸`)
 - **After**/**Bind** (`⟜`)
 
-The somewhat complicated definition of Valences could be replaced with `{𝔽𝕩;𝕨𝔾𝕩}` using headers. However, reference.bqn uses a simple subset of BQN's syntax that doesn't include headers. Instead, the definition relies on the fact that `𝕨` works like `·` if no left argument is given: `(1˙𝕨)-0` is `1-0` or `1` if `𝕨` is present and `(1˙·)-0` otherwise: this reduces to `·-0` or `0`.
-
 ### Array properties
 
 The reference implementations extend Shape (`≢`) to atoms as well as arrays, in addition to implementing other properties. In all cases, an atom behaves as if it has shape `⟨⟩`. The functions in this section never cause an error.
diff --git a/spec/reference.bqn b/spec/reference.bqn
index afd8ccfb..617b88d2 100644
--- a/spec/reference.bqn
+++ b/spec/reference.bqn
@@ -43,9 +43,9 @@ HasFill    # Whether 𝕩 has a fill value
 # Combinators
 ◶ ← {𝕨((𝕨𝔽𝕩)⊑𝕘){𝔽}𝕩}     # LIMITED to number left operand result
 ˙ ← {𝕩⋄𝕗}
-⊘ ← {𝕨((1˙𝕨)-0)◶𝔽‿𝔾 𝕩}
+⊘ ← {𝔽𝕩;𝕨𝔾𝕩}
 ⊢ ← {𝕩}
-⊣ ← {𝕩}⊘{𝕨}
+⊣ ← {𝕩;𝕨}
 ˜ ← {𝕩𝔽𝕨⊣𝕩}
 ∘ ← {𝔽𝕨𝔾𝕩}
 ○ ← {(𝔾𝕨)𝔽𝔾𝕩}
@@ -192,7 +192,7 @@ Depth←IsArray◶0‿{1+0⌈´Depth¨⥊𝕩}
 # LAYER 4: Operators
 
 > ↩ Merge⍟IsArray  ⊘ >
-⋈ ← {⟨𝕩⟩} ⊘ {⟨𝕨,𝕩⟩}
+⋈ ← {⟨𝕩⟩;⟨𝕨,𝕩⟩}
 ≍ ← >∘⋈
 ⎉ ← _rankOp_
 ⚇ ← _depthOp_
@@ -218,7 +218,7 @@ ValidateRanks←{
 }
 _ranks ← {⟨2⟩⊘⟨1,0⟩ ((⊣-1+|)˜⟜≠⊑¨<∘⊢) ValidateRanks∘𝔽}
 _depthOp_←{
-  neg←0>n←𝕨𝔾_ranks𝕩 ⋄ F←𝔽 ⋄ B←{𝕏}⊘{𝕨˙⊸𝕏}
+  neg←0>n←𝕨𝔾_ranks𝕩 ⋄ F←𝔽 ⋄ B←{𝕏;𝕨˙⊸𝕏}
   _d←{
     R←(𝕗+neg)_d
     𝕨(2⥊(neg∧𝕗≥0)∨(0⌈𝕗)≥⋈○≡)◶(⟨R¨⋄R⟜(𝕩˙)¨∘⊣⟩≍⟨(𝕨 B r)¨∘⊢⋄F⟩)𝕩
-- 
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