/
parse.gleam
57 lines (49 loc) · 1.03 KB
/
parse.gleam
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import snag.{Result}
import gleam/int
import gleam/list
import gleam/string
import gleam/result
pub fn int(s: String) -> Result(Int) {
s
|> int.parse()
|> result.replace_error(
["failed to parse \"", s, "\" as int"]
|> string.concat()
|> snag.new(),
)
}
pub fn valid_int(
s: String,
is_valid: fn(Int) -> Bool,
invalid_msg: String,
) -> Result(Int) {
try i = int(s)
case is_valid(i) {
False -> snag.error(invalid_msg)
True -> Ok(i)
}
}
fn greater_than_0(i: Int) -> Bool {
i > 0
}
fn less_than_26(i: Int) -> Bool {
i < 26
}
pub type Day =
Int
fn valid_day(i: Int) -> Bool {
greater_than_0(i) && less_than_26(i)
}
pub fn day(s: String) -> Result(Day) {
valid_int(s, valid_day, "day must be an integer from 1 to 25")
|> snag.context(string.concat(["invalid day value ", "'", s, "'"]))
}
pub fn days(l: List(String)) -> Result(List(Day)) {
case l {
[] -> snag.error("no days selected")
_ ->
l
|> list.try_map(day)
|> snag.context("could not map day values to integers")
}
}