Commit 75bbce9e authored by Robert Griesemer's avatar Robert Griesemer

- added language to document .() notation

- propose change to char/string productions: I find this easier to read

SVN=116037
parent a0d5d808
The Go Programming Language
----
(March 28, 2008)
(April 17, 2008)
This document is an informal specification/proposal for a new systems programming
language.
......@@ -402,15 +402,15 @@ Character and string literals are similar to C except:
The rules are:
char_lit = "'" ( unicode_value | byte_value ) "'" .
unicode_value = utf8_char | little_u_value | big_u_value | escaped_char .
byte_value = octal_byte_value | hex_byte_value .
octal_byte_value = "\" oct_digit oct_digit oct_digit .
hex_byte_value = "\" "x" hex_digit hex_digit .
little_u_value = "\" "u" hex_digit hex_digit hex_digit hex_digit .
big_u_value = "\" "U" hex_digit hex_digit hex_digit hex_digit
hex_digit hex_digit hex_digit hex_digit .
escaped_char = "\" ( "a" | "b" | "f" | "n" | "r" | "t" | "v" | "\" | "'" | "\"" ) .
char_lit = "'" ( utf8_char_no_single_quote | "\" esc_seq ) "'" .
esc_seq =
"a" | "b" | "f" | "n" | "r" | "t" | "v" | "\" | "'" | "\"" |
oct_digit oct_digit oct_digit |
"x" hex_digit hex_digit |
"u" hex_digit hex_digit hex_digit hex_digit |
"U" hex_digit hex_digit hex_digit hex_digit
hex_digit hex_digit hex_digit hex_digit .
A unicode_value takes one of four forms:
......@@ -457,8 +457,8 @@ Double-quoted strings have the usual properties; back-quoted strings
do not interpret backslashes at all.
string_lit = raw_string_lit | interpreted_string_lit .
raw_string_lit = "`" { utf8_char } "`" .
interpreted_string_lit = "\"" { unicode_value | byte_value } "\"" .
raw_string_lit = "`" { utf8_char_no_back_quote } "`" .
interpreted_string_lit = "\"" { utf8_char_no_double_quote | "\\" esc_seq } "\"" .
A string literal has type 'string'. Its value is constructed by
taking the byte values formed by the successive elements of the
......@@ -1078,7 +1078,8 @@ Expression syntax is based on that of C but with fewer precedence levels.
PrimaryExpr =
identifier | Literal | "(" Expression ")" | "iota" |
Call | Conversion | Allocation |
Expression "[" Expression [ ":" Expression ] "]" | Expression "." identifier .
Expression "[" Expression [ ":" Expression ] "]" | Expression "." identifier |
Expression "." "(" Type ")" .
Call = Expression "(" [ ExpressionList ] ")" .
Conversion = TypeName "(" [ ExpressionList ] ")" .
......@@ -1092,8 +1093,9 @@ Expression syntax is based on that of C but with fewer precedence levels.
unary_op = "+" | "-" | "!" | "^" | "<" | ">" | "*" | "&" .
Field selection ('.') binds tightest, followed by indexing ('[]') and then calls and conversions.
The remaining precedence levels are as follows (in increasing precedence order):
Field selection and type assertions ('.') bind tightest, followed by indexing ('[]')
and then calls and conversions. The remaining precedence levels are as follows
(in increasing precedence order):
Precedence Operator
1 ||
......
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