From f3fcc2928931c8ec0ca0770f71c52f5567390b10 Mon Sep 17 00:00:00 2001 From: Marshall Lochbaum Date: Sun, 21 Mar 2021 15:11:37 -0400 Subject: Framing for specification, and discussion of implementation-defined aspects --- docs/spec/index.html | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'docs/spec/index.html') diff --git a/docs/spec/index.html b/docs/spec/index.html index 71d7c6f6..5c2017e1 100644 --- a/docs/spec/index.html +++ b/docs/spec/index.html @@ -5,9 +5,9 @@
BQN / main

BQN specification

-

This directory gives a specification for BQN. The specification differs from the documentation in that its purpose is only to describe the exact details of BQN's operation in the most quickly accessible way, rather than to explain the core ideas of BQN functionality and how it might be used.

-

The core of BQN, which excludes system-provided values, is now completely specified, although the spec will continue to be edited further to improve clarity and cover edge cases that were missed initially.

-

The BQN specification consists of the following documents:

+

This document, and the others in this directory (linked in the list below) make up the pre-versioning BQN specification. The specification differs from the documentation in that its purpose is only to describe the exact details of BQN's operation in the most quickly accessible way, rather than to explain the central ideas of BQN functionality and how it might be used. The core of BQN, which excludes system-provided values, is now almost completely specified. Three planned features—syntax for system-provided values, inferred property function headers, and an extension to allow low-rank elements in the argument to Join—have not yet been added, and the spec will continue to be edited further to improve clarity and cover any edge cases that have been missed.

+

Under this specification, a language implementation is a BQN pre-version implementation if it behaves as specified for all input programs. It is a BQN pre-version implementation with extensions if it behaves as specified in all cases where the specification does not require an error, but behaves differently in at least one case where it requires an error. It is a partial version of either of these if it doesn't conform to the description but differs from a conforming implementation only by rejecting with an error some programs that the conforming implementation accepts. As the specification is not yet versioned, other instances of the specification define these terms in different ways. An implementation can use one of these term if it conforms to any instance of the pre-versioning BQN specifications that defines them. When versioning is begun, there will be only one specification for each version.

+

The following documents are included in the BQN specification. A BQN program is a sequence of Unicode code points: to evaluate it, it is converted into a sequence of tokens using the token formation rules, then these tokens are arranged in a syntax tree according to the grammar, and then this tree is evaluated according to the evaluation semantics. The program may be evaluated in the presence of additional context such as a filesystem or command-line arguments; this context is presented to the program and manipulated through the system-provided values.

+

In several cases, an implementation can choose between more than one possible behavior.

+ -- cgit v1.2.3