From a1b60a18922e578a97e50efe1a2e29863b6f8d92 Mon Sep 17 00:00:00 2001 From: Marshall Lochbaum Date: Sun, 17 Apr 2022 18:00:17 -0400 Subject: Fix the spec's treatment of multiple bodies and predicates --- docs/spec/grammar.html | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'docs/spec/grammar.html') diff --git a/docs/spec/grammar.html b/docs/spec/grammar.html index 19425e06..139a5dd4 100644 --- a/docs/spec/grammar.html +++ b/docs/spec/grammar.html @@ -86,14 +86,15 @@ | FuncName "˜"? "⁼" | lhsComp -

A block is written with braces. It contains bodies, which are lists of statements, separated by semicolons. Multiple bodies can handle different cases, as determined by headers and predicates. A header is written before its body with a separating colon, and an expression other than the last in a body can be made into a predicate by following it with the separator-like ?. A block can have any number of bodies with headers. After these there can be bodies without headers—up to one for an immediate block and up to two for a block with arguments. If a block with arguments has one such body, it's ambivalent, but two of them refer to the monadic and dyadic cases.

+

A block is written with braces. It contains bodies, which are lists of statements, separated by semicolons. Multiple bodies can handle different cases, as determined by headers and predicates. A header is written before its body with a separating colon, and an expression other than the last in a body can be made into a predicate by following it with the separator-like ?.

+

An I_CASE, A_CASE, or S_CASE is called a general case or general body if it has no header or predicate, or, more formally, it doesn't directly include a ":" token and its BODY node doesn't use the EXPR ⋄? "?" ⋄? case. A program must satisfy some additional rules regarding general cases, but these are not needed to resolve the grammar and shouldn't strictly be considered part of it. First, no general body can appear before a body that isn't general in a block. Second, a IMM_BLK or blSub can directly contain at most one general body and an ARG_BLK at most two (these are monadic and dyadic cases).

BODY     = ⋄? ( STMT ⋄ | EXPR ⋄? "?" ⋄? )* STMT ⋄?
-CASE     = BODY
-I_CASE   = ⋄? IMM_HEAD ⋄? ":" BODY
-A_CASE   = ⋄? ARG_HEAD ⋄? ":" BODY
-IMM_BLK  = "{" ( I_CASE ";" )* ( I_CASE | CASE ) "}"
-ARG_BLK  = "{" ( A_CASE ";" )* ( A_CASE | CASE ( ";" CASE )? ) "}"
-blSub    = "{" ( ⋄? s ⋄? ":" )? BODY "}"
+I_CASE   = ( ⋄? IMM_HEAD ⋄? ":" )? BODY
+A_CASE   = ( ⋄? ARG_HEAD ⋄? ":" )? BODY
+S_CASE   = ( ⋄? s        ⋄? ":" )? BODY
+IMM_BLK  = "{" ( I_CASE ";" )* I_CASE "}"
+ARG_BLK  = "{" ( A_CASE ";" )* A_CASE "}"
+blSub    = "{" ( S_CASE ";" )* S_CASE "}"
 BlFunc   =           ARG_BLK
 _blMod1  = IMM_BLK | ARG_BLK
 _blMod2_ = IMM_BLK | ARG_BLK
-- 
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