X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;f=Chapters%2FNormalization.tex;h=6853d88d704b166eaed7ccb0b3964b2d4f284afb;hb=bdb7127d5c2577ef2d68d1efff9256f46917b87d;hp=1f9f62be9bb633171419c7e4ab4a3c4a82c1d6f3;hpb=b1f08ad1bc712b096ea8330252e7a343955004f7;p=matthijs%2Fmaster-project%2Freport.git diff --git a/Chapters/Normalization.tex b/Chapters/Normalization.tex index 1f9f62b..6853d88 100644 --- a/Chapters/Normalization.tex +++ b/Chapters/Normalization.tex @@ -1,4 +1,4 @@ -\chapter{Normalization} +\chapter[chap:normalization]{Normalization} % A helper to print a single example in the half the page width. The example % text should be in a buffer whose name is given in an argument. @@ -7,7 +7,7 @@ % will end up on a single line. The strut=no option prevents a bunch of empty % space at the start of the frame. \define[1]\example{ - \framed[offset=1mm,align=right,strut=no]{ + \framed[offset=1mm,align=right,strut=no,background=box,frame=off]{ \setuptyping[option=LAM,style=sans,before=,after=] \typebuffer[#1] \setuptyping[option=none,style=\tttf] @@ -230,10 +230,10 @@ the core language in a notation that resembles lambda calculus. Each of these transforms is meant to be applied to every (sub)expression in a program, for as long as it applies. Only when none of the -expressions can be applied anymore, the program is in normal form. We -hope to be able to prove that this form will obey all of the constraints -defined above, but this has yet to happen (though it seems likely that -it will). +transformations can be applied anymore, the program is in normal form (by +definition). We hope to be able to prove that this form will obey all of the +constraints defined above, but this has yet to happen (though it seems likely +that it will). Each of the transforms will be described informally first, explaining the need for and goal of the transform. Then, a formal definition is @@ -684,7 +684,7 @@ arguments into normal form. The goal here is to: When looking at the arguments of a user-defined function, we can divide them into two categories: \startitemize - \item Arguments with a runtime representable type (\eg bits or vectors). + \item Arguments of a runtime representable type (\eg bits or vectors). These arguments can be preserved in the program, since they can be translated to input ports later on. However, since we can @@ -720,7 +720,7 @@ When looking at the arguments of a builtin function, we can divide them into categories: \startitemize - \item Arguments with a runtime representable type. + \item Arguments of a runtime representable type. As we have seen with user-defined functions, these arguments can always be reduced to a simple variable reference, by the @@ -729,7 +729,7 @@ into categories: functions can be limited to signal references, instead of needing to support all possible expressions. - \item Arguments with a function type. + \item Arguments of a function type. These arguments are functions passed to higher order builtins, like \lam{map} and \lam{foldl}. Since implementing these @@ -973,247 +973,3 @@ x = let x = add 1 2 in x \stopbuffer \transexample{Return value simplification}{from}{to} - -\subsection{Example sequence} - -This section lists an example expression, with a sequence of transforms -applied to it. The exact transforms given here probably don't exactly -match the transforms given above anymore, but perhaps this can clarify -the big picture a bit. - -TODO: Update or remove this section. - -\startlambda - λx. - let s = foo x - in - case s of - (a, b) -> - case a of - High -> add - Low -> let - op' = case b of - High -> sub - Low -> λc.λd.c - in - λc.λd.op' d c -\stoplambda - -After top-level η-abstraction: - -\startlambda - λx.λc.λd. - (let s = foo x - in - case s of - (a, b) -> - case a of - High -> add - Low -> let - op' = case b of - High -> sub - Low -> λc.λd.c - in - λc.λd.op' d c - ) c d -\stoplambda - -After (extended) β-reduction: - -\startlambda - λx.λc.λd. - let s = foo x - in - case s of - (a, b) -> - case a of - High -> add c d - Low -> let - op' = case b of - High -> sub - Low -> λc.λd.c - in - op' d c -\stoplambda - -After return value extraction: - -\startlambda - λx.λc.λd. - let s = foo x - r = case s of - (a, b) -> - case a of - High -> add c d - Low -> let - op' = case b of - High -> sub - Low -> λc.λd.c - in - op' d c - in - r -\stoplambda - -Scrutinee simplification does not apply. - -After case binder wildening: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> - case a of - High -> add c d - Low -> let op' = case b of - High -> sub - Low -> λc.λd.c - in - op' d c - in - r -\stoplambda - -After case value simplification - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> r' - rh = add c d - rl = let rll = λc.λd.c - op' = case b of - High -> sub - Low -> rll - in - op' d c - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After let flattening: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> r' - rh = add c d - rl = op' d c - rll = λc.λd.c - op' = case b of - High -> sub - Low -> rll - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After function inlining: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> r' - rh = add c d - rl = (case b of - High -> sub - Low -> λc.λd.c) d c - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After (extended) β-reduction again: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> r' - rh = add c d - rl = case b of - High -> sub d c - Low -> d - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After case value simplification again: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> r' - rh = add c d - rlh = sub d c - rl = case b of - High -> rlh - Low -> d - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After case removal: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = r' - rh = add c d - rlh = sub d c - rl = case b of - High -> rlh - Low -> d - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After let bind removal: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - rh = add c d - rlh = sub d c - rl = case b of - High -> rlh - Low -> d - r' = case a of - High -> rh - Low -> rl - in - r' -\stoplambda - -Application simplification is not applicable.