compact-iupac.md
In glyrepr: Representation for Glycan Compositions and Structures

character recovery preserves repeated failures and canonical duplicates

Code
  result <- as_glycan_structure(x, on_failure = "na")
Condition
  Warning:
  2 structures failed validation and were replaced with `NA`.
  x Position 2 (`bad`): Could not parse IUPAC-condensed string: "not-a-structure" i Invalid characters or format in IUPAC-condensed string and Position 4 (`bad_again`): Could not parse IUPAC-condensed string: "not-a-structure" i Invalid characters or format in IUPAC-condensed string

strict character errors retain parse-before-validation precedence

Code
  as_glycan_structure(c("Gal(b1-4)[Man(a1-4)]Glc", "not-a-structure"))
Condition
  Error in `purrr::map()`:
  i In index: 2.
  Caused by error in `value[[3L]]()`:
  ! Could not parse IUPAC-condensed string: "not-a-structure"
  i Invalid characters or format in IUPAC-condensed string