diff options
Diffstat (limited to 'src/interp/parse.boot')
| -rw-r--r-- | src/interp/parse.boot | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/src/interp/parse.boot b/src/interp/parse.boot index a706d174..d403931c 100644 --- a/src/interp/parse.boot +++ b/src/interp/parse.boot @@ -40,6 +40,15 @@ namespace BOOT ++ If non nil, holds the operator being being defined. $defOp := nil +++ When true, means that we are building a compile time value. For +++ the parse tree transformer, this means that some assumtpions +++ are made about certain operators, regardless of their types +++ and semantics. For example `x >= y' is assumed to have the +++ same semantics as `not(x < y)'. Note that this normalization +++ is also done when this parser is used to translate Boot codes +++ to Lisp. That usage is being phased out though. +$normalizeTree := false + parseTransform: %ParseForm -> %Form parseTransform x == $defOp: local:= nil @@ -285,12 +294,10 @@ parseGreaterThan: %ParseForm -> %Form parseGreaterThan t == t isnt [op,x,y] => systemErrorHere "parseGreaterThan" [substitute("<",">",op),parseTran y,parseTran x] - parseGreaterEqual: %ParseForm -> %Form parseGreaterEqual u == parseTran ["not",[substitute("<",">=",first u),:rest u]] - parseLessEqual: %ParseForm -> %Form parseLessEqual u == @@ -298,7 +305,8 @@ parseLessEqual u == parseNotEqual: %ParseForm -> %Form parseNotEqual u == - parseTran ["not",[substitute("=","^=",first u),:rest u]] + $normalizeTree => parseTran ["not",[substitute("=","^=",first u),:rest u]] + u parseAnd: %ParseForm -> %Form parseAnd t == @@ -317,7 +325,7 @@ parseOr t == null rest u => first u (x:= parseTran first u) is ["not",y] => parseIf ["IF",y,parseOr ["or",:rest u],"true"] - true => parseIf ["IF",x,"true",parseOr ["or",:rest u]] + parseIf ["IF",x,"true",parseOr ["or",:rest u]] parseEquivalence: %ParseForm -> %Form @@ -420,8 +428,8 @@ parseIf t == t isnt ["IF",p,a,b] => t ifTran(parseTran p,parseTran a,parseTran b) where ifTran(p,a,b) == - null($InteractiveMode) and p="true" => a - null($InteractiveMode) and p="false" => b + not $InteractiveMode and p="true" => a + not $InteractiveMode and p="false" => b p is ["not",p'] => ifTran(p',b,a) p is ["IF",p',a',b'] => ifTran(p',ifTran(a',COPY a,COPY b),ifTran(b',a,b)) p is ["SEQ",:l,["exit",1,p']] => |