From cf21069959352da95314d3148994f2c45f51f50f Mon Sep 17 00:00:00 2001
From: tslil <tslil@posteo.de>
Date: Sun, 19 Oct 2025 15:07:21 +0100
Subject: Trains should be left associative and hooks should be right
 associative

---
 rprt.md | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

(limited to 'rprt.md')

diff --git a/rprt.md b/rprt.md
index fc1a7f6..394f994 100644
--- a/rprt.md
+++ b/rprt.md
@@ -98,7 +98,7 @@ RPRT provides two explicit hook combinators from BQN for flexible function compo
 - Monadic: `(F<G) ω = ω F (G ω)`
 - Dyadic: `α (F<G) ω = α F (G ω)`
 
-These combinators bind more tightly than trains and enable partial application patterns. Hooks are **left-associative**, following BQN's modifier associativity: `F<G<H` parses as `(F<G)<H`.
+These combinators bind more tightly than trains and enable partial application patterns. Hooks are **right-associative**, the _opposite_ of BQN's modifier associativity: `F<G<H` parses as `F<(G<H)`.
 
 ## 1.3 The Editor State Monad
 
@@ -144,13 +144,15 @@ The grouping operator `{}` provides transactional semantics: all operations with
 
 # 1.7 Composition and Parsing
 
-**Precedence and Associativity:** Following BQN rules:
+**Precedence and Associativity:**:
 - Hooks bind tighter than trains
-- Hooks are left-associative: `F<G<H` = `(F<G)<H`
-- Trains are right-associative: `F G H I` = `F (G H I)`
+- Hooks are right-associative: `F<G<H` = `F<(G<H)`
+- Trains are left-associative: `F G H I` = `(F G) H I`
 - Functions and operators apply left-to-right
 - Dyadic functions are infix
 
+Note that the associativity of operations here is _reversed_ compared to BQN. Our reasoning for breaking with this convention is purely for convenience of the user: the monadic semantics for search functions is given on a _left_ argument, which matches the usual order in which expressions are made, "first select this, then using that selection do that, then ...".
+
 
 # 2. Selection Functions
 
@@ -378,10 +380,10 @@ Text operations follow the broadcasting rules described in §1.2. When the text
 ```
 | "date"                # Run date with no input, returns selection to output
 /pattern/ c (| "date")  # Replace pattern with date command output
-α c<(|<"sort")          # Pipe selection through sort, replace with result (using After hooks)
+α c<|<"sort"          # Pipe selection through sort, replace with result (using After hooks)
 ```
 
-The third example composes two After hooks (§1.2): `|<"sort"` creates a monadic function that pipes its argument through sort, where `"sort"` is treated as a constant Text function (§1.1). Then `α c<(|<"sort")` expands to `α c ((|<"sort") α)` = `α c (α | "sort")`, avoiding explicit repetition of the selection. Note that parentheses are necessary because hooks are left-associative: without them, `c<|<"sort"` would parse as `(c<|)<"sort"`, which expands to `α (c<|) "sort"` = `α c (| "sort")`, incorrectly running sort with no input.
+The third example composes two After hooks (§1.2): `|<"sort"` creates a monadic function that pipes its argument through sort, where `"sort"` is treated as a constant Text function (§1.1). Then `α c<|<"sort"` expands to `α c ((|<"sort") α)` = `α c (α | "sort")`, avoiding explicit repetition of the selection. Note that parentheses are not necessary because hooks are right-associative.
 
 ## 3.2 Text Function Operators
 
-- 
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