Parse hooks, these are left associative

1 files changed, 9 insertions, 7 deletions

diff --git a/rprt.md b/rprt.md
index 5bcbec5..fc1a7f6 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.
+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`.
 
 ## 1.3 The Editor State Monad
 
@@ -144,8 +144,10 @@ The grouping operator `{}` provides transactional semantics: all operations with
 
 # 1.7 Composition and Parsing
 
-**Precedence:** Following BQN rules:
-- Operators bind tighter than functions
+**Precedence and Associativity:** Following BQN rules:
+- 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)`
 - Functions and operators apply left-to-right
 - Dyadic functions are infix
 
@@ -374,12 +376,12 @@ Text operations follow the broadcasting rules described in §1.2. When the text
 **Examples:**
 
 ```
-| "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)
+| "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)
 ```
 
-The third example composes two After hooks (§1.2): `|<"sort"` creates a monadic selection 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 (α | "sort")`, avoiding explicit repetition of the selection. Note the parentheses are necessary: `c<|<"sort"` would incorrectly parse as `α c (| "sort")`, 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 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.
 
 ## 3.2 Text Function Operators