diff options
Diffstat (limited to 'src/interp/g-opt.boot')
| -rw-r--r-- | src/interp/g-opt.boot | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/src/interp/g-opt.boot b/src/interp/g-opt.boot index eb3c3e86..a4b4f549 100644 --- a/src/interp/g-opt.boot +++ b/src/interp/g-opt.boot @@ -289,11 +289,14 @@ coagulateWhenSeries(x,tag) == nil nil -++ Return true if the expression `x' exist the scope with tag `g' +++ Return non-nil if the expression `x' exist the scope with tag `g' ++ by normal local transfer or by exiting the enclosing function -++ with a `return' statement. +++ with a `return' statement. If non-nil, the return value is the +++ expression operand to the normal exit. exitScope?(x,g) == - x is ['%leave,=g,:.] or x is ['%return,:.] + x is ['%leave,=g,y] and hasNoLeave?(y,g) => y + x is ['%return,:.] => x + nil unnestWhen! x == f x where f x == @@ -348,15 +351,23 @@ spliceSeq! x == walkWith!(x,function f) where x.args := spliceSeqArgs x.args x +++ Return the list of reduced clauses if every branch is a simple +++ normal exiting expression. Otherwise, return nil. +exitClauses(l,g) == + [[p,x] for cl in l | cl is [p,u] and (x := exitScope?(u,g)) or leave nil] + ++ Remove superfluous cancel/scope pairs exposed by running ++ removeJunk!. cancelScopeLeave! x == walkWith!(x,function f) where f x == - x is ['%scope,g,['%leave,=g,y]] and hasNoLeave?(y,g) => - resetTo(x,f y) - x is ['%scope,g,u:=['%return,.,y]] => resetTo(x,u) + x is ['%scope,g,u] => + u is ['%when,:.] and (v := exitClauses(u.args,g)) => + resetTo(x,['%when,:v]) + y := exitScope?(u,g) => resetTo(x,f y) + x x +++ Remove redundant %leave opode around %return forms. removeLeave! x == walkWith!(x,function f) where f x == x is ['%leave,.,y] and y is ['%return,:.] => resetTo(x,y) |