diff --git a/Tutorial:-Hacking-the-Nimrod-compiler:-Pragmas.md b/Tutorial:-Hacking-the-Nimrod-compiler:-Pragmas.md deleted file mode 100644 index 4079005..0000000 --- a/Tutorial:-Hacking-the-Nimrod-compiler:-Pragmas.md +++ /dev/null @@ -1,73 +0,0 @@ -## Introduction -As there are no tutorials (that I know of) on how to add new features to the nimrod -compiler I have decided to make one, based on me implementing the `requires` -pragma which will be used for Babel Packages. - -As with many tasks there are many tools that are very helpful, I have used -the *nimgrep* tool which is in the tools/ directory in Nimrod's repository, but I'm sure you know of other tools which can be very helpful! - -## First steps -The first thing I have decided to do was create a test file, it follows: - - {.requires packageA "0.7" "0.9".} - echo("hi") - -(It originally had a `..` between the two string literals, I decided to get rid -of that because I noticed that pragmas don't support it, I might come back to it.) - -I then saved that file as *"pragmaTest.nim"* and compiled it with -`nimrod c pragmaTest.nim`. This has caused `pragmaTest.nim(1, 10) Error: invalid pragma: requires`. - -The next step was quite obvious, searching for "invalid pragma:", `nimgrep --recursive --ext:nim "invalid\ pragma:"`, -this only gives one result. - - ../Nimrod/rod/msgs.nim - 258: errInvalidPragmaX: "invalid pragma: $1", - -After some more intellectual grepping and looking through files, I noticed that the pragma() function in pragmas.nim -takes an argument called `validPragmas` this lead me to *semtypes.nim* and *semstmts.nim* -after searching for (yes, you've guessed it) `pragma(`(please note this needs escaping when used as a regex). - -There was many `pragma` calls, I have looked at most of them and since I wanted -a "global"(not sure if that's the correct term) pragma, for example -`{.warning: "warning".}`. The `pragma` function is called with many different -valid pragma groups. There is among many others, `stmtPragmas`, which is what -I wanted, it's defined in *pragmas.nim*. - -## Hacking the code! -I found where `TSpecialWords` is defined(*wordrecg.nim*) and added `wRequires` -there, to the `specialWords` array below, and also to `stmtPragmas`. I then added `wRequires` to the case statement in the `pragma` function in *pragmas.nim*. - -This is where the `debug` function came into play, it is a function that pretty prints a -node in the AST, it is very useful. I added two `debug` calls one for the 'it' node -and another one for the 'n' node. - -I then bootstrapped by executing `./koch boot`. After I got the beautiful "SUCCESS", -I compiled *pragmaTest.nim*. And I got this output: - - { - "kind": "nkIdent", - "ident": "requires" - } - { - "kind": "nkPragma", - "sons": [ - { - "kind": "nkIdent", - "ident": "requires" - }, - { - "kind": "nkIdent", - "ident": "packageA" - }, - { - "kind": "nkStrLit", - "strVal": "0.7" - }, - { - "kind": "nkStrLit", - "strVal": "0.9" - } - ] - } -