## THIS HAS BEEN MOVED TO UTILS


allPosCombsList <- function(dat, choose=seq(ncol(dat)), yName="y") {
## returns list of column indicies

    #----------------------------------------------------------------------#
    ## NOTE TO SELF
    ##   CANNOT DO THIS.   dat must not contain y.  otherwise the columns will not match up
    ## 
    ##  This will simply have to be different from allModels for now
    ##
    # if (!any(colnames(dat) == yName)) 
    #   warning(yname, " not found in the colnames of dat; using whole dataframe.")
    #
    # # remove y-column 
    # dat <- dat[, colnames(dat) != yName]
    #----------------------------------------------------------------------#    
    
    n <- ncol(dat)

    # x <- c(rep(TRUE, 3), rep(FALSE, n-3))
    lapply(choose, function(r) cbind(permutations(n, r)))
}

#  allPosCombsMatrix.TakesTooLong <- function(dat, choose=-1) { 
#  ## Creates a matrix where each row is a logical-index corresponding  
#  ## to the columns (ie, variables) of dat 
#  ## Where the rows contain all possible 'choose'-combinations of the variables 
#  ##   
#  ## dat is a dataframe of response variables 
#  ## choose is a vector, indicating HOW MANY variables to co-select 
#  ##   eg  choose=3  will give only rows of 3-co-selections 
#  ##       choode=1:3 will give only rows of 1, 2, or 3 co-selections 
#  ##   choose=-1 selects ALL rows 
#   
#      n <- ncol(dat) 
#   
#      matr <- matrix(rep(c(TRUE, FALSE), n), nrow=n, byrow=TRUE) 
#      matr <- do.call(expand.grid, split(matr, row(matr))) 
#   
#      # reverse the columns for neatness 
#      matr <- matr[, n:1] 
#   
#      # add names 
#      colnames(matr) <- colnames(dat) 
#   
#      # if choose is flagged as -1, select all rows, otherwise only those requested 
#      whichRows <- if (all(choose == (-1))) seq(2^n) else rowSums(matr) %in% choose 
#   
#      # return 
#      matr[whichRows, ] 
#   
#  } 



formulasList <- function(dat, yName="y", VARS.list=NULL, interact=TRUE, intercept=TRUE)  {
  # creates list of formula strings from a dataframe and list of variable indexes
  #   Note:  VARS.INDEX should reference dat WITHOUT y present. 

  plusstar <- if (interact) "*" else "+"

  if (is.null(VARS.list))
    VARS.list <- allPosCombsList(dat[colnames(dat) != yName], 1:2)
  
  tilde   <- ifelse(intercept, "~ 1", "~ -1")
  vars    <- colnames(dat[colnames(dat) != yName])
  #  datName <- as.character(match.call()[[2]])  # NOT NEEDED

  formulasList <- lapply(VARS.list, function(varsIndex)
                     apply(varsIndex, 1, function(vec) 
                        as.character(paste(c( paste(yName, tilde), vars[vec]), collapse=plusstar), env=parent.frame(3)) 
                    ))

  formulasList
}