You can get or set attributes with the attr
function.
attr(terms(myFormula), "factors")
You can find available methods for formulae using the methods
function.
methods(class = "formula")
## [1] [.formula* aggregate.formula* alias.formula* all.equal.formula
## [5] ansari.test.formula* bartlett.test.formula* boxplot.formula* cdplot.formula*
## [9] cor.test.formula* deriv.formula deriv3.formula fligner.test.formula*
## [13] formula.formula* friedman.test.formula* ftable.formula* getInitial.formula*
## [17] kruskal.test.formula* lines.formula* mood.test.formula* mosaicplot.formula*
## [21] pairs.formula* plot.formula* points.formula* ppr.formula*
## [25] prcomp.formula* princomp.formula* print.formula quade.test.formula*
## [29] selfStart.formula* spineplot.formula* stripchart.formula* sunflowerplot.formula*
## [33] t.test.formula* terms.formula text.formula* update.formula
## [37] var.test.formula* wilcox.test.formula*