commit 2c8697696dc32314f9a2f75c788719b74bcac5ee
parent ef68ab406682f3200796e5e302ba984ff56d7b0d
Author: Quentin Carbonneaux <quentin@c9x.me>
Date: Thu, 12 May 2022 09:18:37 +0200
use an alias for \n in the il spec
Diffstat:
| M | doc/il.txt | | | 41 | +++++++++++++++++++++-------------------- |
1 file changed, 21 insertions(+), 20 deletions(-)
diff --git a/doc/il.txt b/doc/il.txt
@@ -11,7 +11,7 @@
* <@ Input Files >
* <@ BNF Notation >
* <@ Sigils >
- * <@ Spaces >
+ * <@ Spacing >
2. <@ Types >
* <@ Simple Types >
* <@ Subtyping >
@@ -83,8 +83,9 @@ below using BNF syntax. The different BNF constructs used
are listed below.
* Keywords are enclosed between quotes;
- * `... | ...` expresses disjunctions;
- * `[ ... ]` marks some syntax as optional;
+ * `... | ...` expresses alternatives;
+ * `( ... )` groups syntax;
+ * `[ ... ]` marks the nested syntax as optional;
* `( ... ),` designates a comma-separated list of the
enclosed syntax;
* `...*` and `...+` are used for arbitrary and
@@ -106,15 +107,18 @@ scope and nature of identifiers.
In this BNF syntax, we use `?IDENT` to designate an identifier
starting with the sigil `?`.
-~ Spaces
-~~~~~~~~
+~ Spacing
+~~~~~~~~~
+
+ `bnf
+ NL := '\n'+
Individual tokens in IL files must be separated by one or
more spacing characters. Both spaces and tabs are recognized
as spacing characters. In data and type definitions, newlines
-can also be used as spaces to prevent overly long lines. When
+may also be used as spaces to prevent overly long lines. When
exactly one of two consecutive tokens is a symbol (for example
-`,` or `=` or `{`), space may be omitted.
+`,` or `=` or `{`), spacing may be omitted.
- 2. Types
----------
@@ -213,9 +217,9 @@ constants by the linker.
`bnf
LINKAGE :=
- 'export' '\n'*
- | 'section' SECNAME '\n'*
- | 'section' SECNAME SECFLAGS '\n'*
+ 'export' [NL]
+ | 'section' SECNAME [NL]
+ | 'section' SECNAME SECFLAGS [NL]
SECNAME := '"' .... '"'
SECFLAGS := '"' .... '"'
@@ -367,9 +371,9 @@ Here are various examples of data definitions.
`bnf
FUNCDEF :=
LINKAGE*
- 'function' [ABITY] $IDENT '(' (PARAM), ')' '\n'*
- '{' '\n'+
- BLOCK+
+ 'function' [ABITY] $IDENT '(' (PARAM), ')' [NL]
+ '{'
+ [NL] BLOCK+
'}'
PARAM :=
@@ -453,13 +457,10 @@ connected using jump instructions.
`bnf
BLOCK :=
- @IDENT '\n'+ # Block label
- PHILINE* # Phi instructions
- INSTLINE* # Regular instructions
- JUMP '\n'+ # Jump or return
-
- PHILINE := PHI '\n'+
- INSTLINE := INST '\n'+
+ @IDENT NL # Block label
+ ( PHI NL )* # Phi instructions
+ ( INST NL )* # Regular instructions
+ JUMP NL # Jump or return
All blocks have a name that is specified by a label at
their beginning. Then follows a sequence of instructions
