improve formatting of null values, closes #48

Author: Enchufa2

NEWS.md

@@ -1,6 +1,7 @@
 # errors 0.4.2
 
 - Add support for PDG rounding rules (@davidchall #59 addressing #45).
+- Improve formatting of null values (#48).
 
 # errors 0.4.1
 

R/print.R

@@ -45,7 +45,7 @@ format.errors = function(x,
 
   e <- signif(.e(x), digits)
   nulle <- e == 0 & !is.na(e)
-  xexp <- get_exponent(x)
+  xexp <- ifelse(.v(x) == 0, get_exponent(e) + 1, get_exponent(x))
   value_digits <- ifelse(e, digits - get_exponent(e), digits)
   value <- ifelse(e, signif(.v(x), xexp + value_digits), .v(x))
   value <- ifelse(is.finite(value), value, .v(x))

tests/testthat/test-print.R

@@ -57,4 +57,8 @@ test_that("error formatting works properly", {
   expect_equal(format(x[3]), "NaN(NaN)")
   expect_equal(format(x[4]), "Inf(Inf)")
   expect_equal(format(x[5]), "-Inf(Inf)")
+
+  x <- set_errors(c(0e10, 1e12), 0.1e12)
+  expect_equal(format(x), c("0.0(1)e12", "1.0(1)e12"))
+  expect_equal(format(x, digits=2), c("0.00(10)e12", "1.00(10)e12"))
 })