diff options
Diffstat (limited to 'spec/01-lexical-syntax.md')
| -rw-r--r-- | spec/01-lexical-syntax.md | 46 |
1 files changed, 27 insertions, 19 deletions
diff --git a/spec/01-lexical-syntax.md b/spec/01-lexical-syntax.md index 53c8caf745..78f1a1a408 100644 --- a/spec/01-lexical-syntax.md +++ b/spec/01-lexical-syntax.md @@ -41,7 +41,7 @@ classes (Unicode general category given in parentheses): 1. Parentheses `‘(’ | ‘)’ | ‘[’ | ‘]’ | ‘{’ | ‘}’ `. 1. Delimiter characters ``‘`’ | ‘'’ | ‘"’ | ‘.’ | ‘;’ | ‘,’ ``. 1. Operator characters. These consist of all printable ASCII characters - `\u0020` - `\u007F` which are in none of the sets above, mathematical + (`\u0020` - `\u007E`) that are in none of the sets above, mathematical symbols (`Sm`) and other symbols (`So`). ## Identifiers @@ -49,11 +49,13 @@ classes (Unicode general category given in parentheses): ```ebnf op ::= opchar {opchar} varid ::= lower idrest +boundvarid ::= varid + | ‘`’ varid ‘`’ plainid ::= upper idrest | varid | op id ::= plainid - | ‘`’ stringLiteral ‘`’ + | ‘`’ { charNoBackQuoteOrNewline | UnicodeEscape | charEscapeSeq } ‘`’ idrest ::= {letter | digit} [‘_’ op] ``` @@ -398,40 +400,46 @@ members of type `Boolean`. ### Character Literals ```ebnf -characterLiteral ::= ‘'’ (printableChar | charEscapeSeq) ‘'’ +characterLiteral ::= ‘'’ (charNoQuoteOrNewline | UnicodeEscape | charEscapeSeq) ‘'’ ``` A character literal is a single character enclosed in quotes. -The character is either a printable unicode character or is described -by an [escape sequence](#escape-sequences). +The character can be any Unicode character except the single quote +delimiter or `\u000A` (LF) or `\u000D` (CR); +or any Unicode character represented by either a +[Unicode escape](01-lexical-syntax.html) or by an [escape sequence](#escape-sequences). > ```scala > 'a' '\u0041' '\n' '\t' > ``` -Note that `'\u000A'` is _not_ a valid character literal because -Unicode conversion is done before literal parsing and the Unicode -character `\u000A` (line feed) is not a printable -character. One can use instead the escape sequence `'\n'` or -the octal escape `'\12'` ([see here](#escape-sequences)). +Note that although Unicode conversion is done early during parsing, +so that Unicode characters are generally equivalent to their escaped +expansion in the source text, literal parsing accepts arbitrary +Unicode escapes, including the character literal `'\u000A'`, +which can also be written using the escape sequence `'\n'`. ### String Literals ```ebnf stringLiteral ::= ‘"’ {stringElement} ‘"’ -stringElement ::= printableCharNoDoubleQuote | charEscapeSeq +stringElement ::= charNoDoubleQuoteOrNewline | UnicodeEscape | charEscapeSeq ``` -A string literal is a sequence of characters in double quotes. The -characters are either printable unicode character or are described by -[escape sequences](#escape-sequences). If the string literal -contains a double quote character, it must be escaped, -i.e. `"\""`. The value of a string literal is an instance of -class `String`. +A string literal is a sequence of characters in double quotes. +The characters can be any Unicode character except the double quote +delimiter or `\u000A` (LF) or `\u000D` (CR); +or any Unicode character represented by either a +[Unicode escape](01-lexical-syntax.html) or by an [escape sequence](#escape-sequences). + +If the string literal contains a double quote character, it must be escaped using +`"\""`. + +The value of a string literal is an instance of class `String`. > ```scala -> "Hello,\nWorld!" -> "This string contains a \" character." +> "Hello, world!\n" +> "\"Hello,\" replied the world." > ``` #### Multi-Line String Literals |