diff --git a/collects/redex/private/pict.rkt b/collects/redex/private/pict.rkt index f3c50a7830..119482d543 100644 --- a/collects/redex/private/pict.rkt +++ b/collects/redex/private/pict.rkt @@ -234,33 +234,37 @@ (rule-pict-rhs rp) (rp->side-condition-pict rp +inf.0)))] [multi-line-spacer - (ghost - (launder - (ctl-superimpose - (apply ctl-superimpose (map mk-top-line-spacer rps)) - (apply ctl-superimpose (map mk-bot-line-spacer rps)))))] + (if (null? rps) + (blank) + (ghost + (launder + (ctl-superimpose + (apply ctl-superimpose (map mk-top-line-spacer rps)) + (apply ctl-superimpose (map mk-bot-line-spacer rps))))))] [spacer (dc void (pict-width multi-line-spacer) (pict-descent multi-line-spacer) ;; probably could be zero ... 0 (pict-descent multi-line-spacer))]) - (apply - vl-append - (add-between - (blank 0 (reduction-relation-rule-separation)) - (map (λ (rp) - (side-condition-combiner - (vl-append - (ltl-superimpose - (htl-append (rule-pict-lhs rp) - (basic-text " " (default-style)) - (arrow->pict (rule-pict-arrow rp))) - (rtl-superimpose - spacer - (rp->pict-label rp))) - (rule-pict-rhs rp)) - (rp->side-condition-pict rp +inf.0))) - rps))))) + (if (null? rps) + (blank) + (apply + vl-append + (add-between + (blank 0 (reduction-relation-rule-separation)) + (map (λ (rp) + (side-condition-combiner + (vl-append + (ltl-superimpose + (htl-append (rule-pict-lhs rp) + (basic-text " " (default-style)) + (arrow->pict (rule-pict-arrow rp))) + (rtl-superimpose + spacer + (rp->pict-label rp))) + (rule-pict-rhs rp)) + (rp->side-condition-pict rp +inf.0))) + rps)))))) (define compact-vertical-min-width (make-parameter 0))