R/processFormulaStatement.R

In USDA-ERS/MTED-TabloToR:

processFormulaStatement = function(s){
  frm = correctFormula(s$parsed$equation)
  #frm = correctFormula(gsub(":","%:%",gsub('>==','>=',gsub('<==','<=',gsub('=','=',s$parsed$equation)))))

  dimensions = s$parsed$elements[grep('\\(all,', s$parsed$elements)]
  qualifiers = gsub('<>', '!=', gsub(':', ",", gsub(
    '=', '==', gsub('\\(all,', 'all(', dimensions)
  )))

  if (length(qualifiers) > 0) {
    condition = list()
    for (l in 1:length(qualifiers)) {
      q = str2lang(qualifiers[[l]])
      if (length(q) == 4) {
        condition[[length(condition) + 1]] = paste0(deparse1(correctFormula(deparse1(q[[4]]))),collapse=' ')
      }
    }

    for (l in 1:length(qualifiers)) {
      q = str2lang(qualifiers[[l]])
      if (l == 1) {
        expr = sprintf(
          'for(%s in %s){%s}',
          paste0(deparse1(q[[2]]),collapse=' '),
          paste0(deparse1(q[[3]]),collapse=' '),
          ifelse(
            length(condition) == 0,
            paste0(deparse1(frm),collapse=' '),
            sprintf(
              'if(%s){%s}',
              paste(condition, collapse = '&'),
              paste0(deparse1(frm), collapse=' ')
            )
          )
        )
      } else {
        expr = sprintf(
          'for(%s in %s){%s}',
          paste0(deparse1(q[[2]]),collapse=' '),
                 paste0(deparse1(q[[3]]),collapse=' '),
          expr
        )
      }
    }
  } else{
    expr = paste0(deparse1(frm),collapse=' ')
  }
  return(paste0(deparse1(sumToMap(str2lang(expr))),collapse=' '))
}