diff options
| -rw-r--r-- | doc/il.txt | 41 |
1 files changed, 21 insertions, 20 deletions
diff --git a/doc/il.txt b/doc/il.txt index fca10df..25fa36b 100644 --- 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 |