diff options
| -rw-r--r-- | doc/il.txt | 44 |
1 files changed, 30 insertions, 14 deletions
diff --git a/doc/il.txt b/doc/il.txt index 6d9345b..fca10df 100644 --- a/doc/il.txt +++ b/doc/il.txt @@ -11,6 +11,7 @@ * <@ Input Files > * <@ BNF Notation > * <@ Sigils > + * <@ Spaces > 2. <@ Types > * <@ Simple Types > * <@ Subtyping > @@ -105,6 +106,16 @@ scope and nature of identifiers. In this BNF syntax, we use `?IDENT` to designate an identifier starting with the sigil `?`. +~ Spaces +~~~~~~~~ + +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 +exactly one of two consecutive tokens is a symbol (for example +`,` or `=` or `{`), space may be omitted. + - 2. Types ---------- @@ -202,9 +213,9 @@ constants by the linker. `bnf LINKAGE := - 'export' - | 'section' SECNAME - | 'section' SECNAME SECFLAGS + 'export' '\n'* + | 'section' SECNAME '\n'* + | 'section' SECNAME SECFLAGS '\n'* SECNAME := '"' .... '"' SECFLAGS := '"' .... '"' @@ -296,7 +307,8 @@ their size between curly braces. `bnf DATADEF := - LINKAGE* 'data' $IDENT '=' ['align' NUMBER] + LINKAGE* + 'data' $IDENT '=' ['align' NUMBER] '{' ( EXTTY DATAITEM+ | 'z' NUMBER ), @@ -354,8 +366,9 @@ Here are various examples of data definitions. `bnf FUNCDEF := - LINKAGE* 'function' [ABITY] $IDENT '(' (PARAM), ')' - '{' + LINKAGE* + 'function' [ABITY] $IDENT '(' (PARAM), ')' '\n'* + '{' '\n'+ BLOCK+ '}' @@ -440,25 +453,28 @@ connected using jump instructions. `bnf BLOCK := - @IDENT # Block label - PHI* # Phi instructions - INST* # Regular instructions - JUMP # Jump or return + @IDENT '\n'+ # Block label + PHILINE* # Phi instructions + INSTLINE* # Regular instructions + JUMP '\n'+ # Jump or return + + PHILINE := PHI '\n'+ + INSTLINE := INST '\n'+ All blocks have a name that is specified by a label at their beginning. Then follows a sequence of instructions that have "fall-through" flow. Finally one jump terminates the block. The jump can either transfer control to another -block of the same function or return; they are described +block of the same function or return; jumps are described further below. The first block in a function must not be the target of -any jump in the program. If this is really needed, -the frontend could insert an empty prelude block +any jump in the program. If a jump to the function start +is needed, the frontend must insert an empty prelude block at the beginning of the function. When one block jumps to the next block in the IL file, -it is not necessary to give the jump instruction, it +it is not necessary to write the jump instruction, it will be automatically added by the parser. For example the start block in the example below jumps directly to the loop block. |