From ceaa82c6d1564b2ca7965c4f29b51f45ad1c2933 Mon Sep 17 00:00:00 2001 From: Marshall Lochbaum Date: Thu, 3 Sep 2020 22:15:24 -0400 Subject: Highlight quotes as strings even if unpaired --- docs/spec/literal.html | 2 +- docs/spec/token.html | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'docs/spec') diff --git a/docs/spec/literal.html b/docs/spec/literal.html index d51bf50f..04491352 100644 --- a/docs/spec/literal.html +++ b/docs/spec/literal.html @@ -6,7 +6,7 @@
BQN

Specification: BQN literal notation

A literal is a single token that indicates a fixed character, number, or array. While literals indicate values of a data type, primitives indicate values of an operation type: function, 1-modifier, or 2-modifier.

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Two types of literal deal with text. As the source code is considered to be a sequence of unicode code points ("characters"), and these code points are also used for BQN's character data type, the representation of a text literal is very similar to its value. In a text literal, the newline character is always represented using the ASCII line feed character, code point 10. A character literal is enclosed with single quotes ' and its value is identical to the single character between them. A string literal is enclosed in double quotes ", and any double quotes between them must come in pairs, as a lone double quote marks the end of the literal. The value of a string literal is a rank-1 array whose elements are the characters in between the enclosing quotes, after replacing each pair of double quotes with only one such quote.

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Two types of literal deal with text. As the source code is considered to be a sequence of unicode code points ("characters"), and these code points are also used for BQN's character data type, the representation of a text literal is very similar to its value. In a text literal, the newline character is always represented using the ASCII line feed character, code point 10. A character literal is enclosed with single quotes ' and its value is identical to the single character between them. A string literal is enclosed in double quotes ", and any double quotes between them must come in pairs, as a lone double quote marks the end of the literal. The value of a string literal is a rank-1 array whose elements are the characters in between the enclosing quotes, after replacing each pair of double quotes with only one such quote.

The format of a numeric literal is more complicated. From the tokenization rules, a numeric literal consists of a numeric character (one of ¯∞π.0123456789) followed by any number of numeric or alphabetic characters. Some numeric literals are valid and indicate a number, while others are invalid and cause an error. The grammar for valid numbers is given below in a BNF variant. Only four alphabetic characters are allowed: "i", which separates the real and imaginary components of a complex number, "e", which functions as in scientific notation, and the uppercase versions of these letters.

number    = component ( ( "i" | "I" ) component )?
 component = mantissa ( ( "e" | "E" ) exponent )?
diff --git a/docs/spec/token.html b/docs/spec/token.html
index 87ae06ab..010c033e 100644
--- a/docs/spec/token.html
+++ b/docs/spec/token.html
@@ -7,7 +7,7 @@
 
Specification: BQN token formation

 
This page describes BQN's token formation rules (token formation is also called scanning). Most tokens in BQN are a single character long, but quoted characters and strings, identifiers, and numbers can consist of multiple characters, and comments, spaces, and tabs are discarded during token formation.

 
BQN source code should be considered as a series of unicode code points, which we refer to as "characters". The separator between lines in a file is considered to be a single character, newline, even though some operating systems such as Windows typically represent it with a two-character CRLF sequence. Implementers should note that not all languages treat unicode code points as atomic, as exposing the UTF-8 or UTF-16 representation instead is common. For a language such as JavaScript that uses UTF-16, the double-struck characters 𝕨𝕎𝕩𝕏𝕗𝔽𝕘𝔾 are represented as two 16-bit surrogate characters, but BQN treats them as a single unit.

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A BQN character literal consists of a single character between single quotes, such as 'a', and a string literal consists of any number of characters between double quotes, such as "" or "abc". Character and string literals take precedence with comments over other tokenization rules, so that # between quotes does not start a comment and whitespace between quotes is not removed, but a quote within a comment does not start a character literal. Almost any character can be included directly in a character or string literal without escaping. The only exception is the double quote character ", which must be written twice to include it in a string, as otherwise it would end the string instead. Character literals require no escaping at all, as the length is fixed. In particular, literals for the double and single quote characters are written ''' and '"', while length-1 strings containing these characters are "'" and """".

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A BQN character literal consists of a single character between single quotes, such as 'a', and a string literal consists of any number of characters between double quotes, such as "" or "abc". Character and string literals take precedence with comments over other tokenization rules, so that # between quotes does not start a comment and whitespace between quotes is not removed, but a quote within a comment does not start a character literal. Almost any character can be included directly in a character or string literal without escaping. The only exception is the double quote character ", which must be written twice to include it in a string, as otherwise it would end the string instead. Character literals require no escaping at all, as the length is fixed. In particular, literals for the double and single quote characters are written ''' and '"', while length-1 strings containing these characters are "'" and """".

 
A comment consists of the hash character # and any following text until (not including) the next newline character. The initial # must not be part of a string literal started earlier. Comments are ignored entirely and do not form tokens.

 
Identifiers and numeric literals share the same token formation rule. These tokens are formed from the numeric characters ¯∞π.0123456789 and alphabetic characters _abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ and the oddball 𝕣. Any sequence of these characters adjacent to each other forms a single token, which is a numeric literal if it begins with a numeric character and an identifier if it begins with an alphabetic character. Numeric literals are also subject to numeric literal rules, which specify which numeric literals are valid and which numbers they represent. If the token contains 𝕣 it must be either 𝕣, _𝕣, or _𝕣_ and is considered a special name (see below). As the value taken by this identifier can only be a modifier, the uppercase character ℝ is not allowed.

 
Following this step, the whitespace characters space and tab are ignored, and do not form tokens. Only these whitespace characters, and the newline character, which does form a token, are allowed.

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