1 files changed, 141 insertions, 0 deletions
diff --git a/library/src/utility/string.rs b/library/src/utility/string.rs
new file mode 100644
index 00000000..ed444d35
--- /dev/null
+++ b/library/src/utility/string.rs
@@ -0,0 +1,141 @@
+use typst::model::Regex;
+
+use crate::prelude::*;
+
+/// The string representation of a value.
+pub fn repr(_: &mut Vm, args: &mut Args) -> SourceResult<Value> {
+    Ok(args.expect::<Value>("value")?.repr().into())
+}
+
+/// Convert a value to a string.
+pub fn str(_: &mut Vm, args: &mut Args) -> SourceResult<Value> {
+    let Spanned { v, span } = args.expect("value")?;
+    Ok(Value::Str(match v {
+        Value::Int(v) => format_str!("{}", v),
+        Value::Float(v) => format_str!("{}", v),
+        Value::Str(v) => v,
+        v => bail!(span, "cannot convert {} to string", v.type_name()),
+    }))
+}
+
+/// Create blind text.
+pub fn lorem(_: &mut Vm, args: &mut Args) -> SourceResult<Value> {
+    let words: usize = args.expect("number of words")?;
+    Ok(Value::Str(lipsum::lipsum(words).into()))
+}
+
+/// Create a regular expression.
+pub fn regex(_: &mut Vm, args: &mut Args) -> SourceResult<Value> {
+    let Spanned { v, span } = args.expect::<Spanned<EcoString>>("regular expression")?;
+    Ok(Regex::new(&v).at(span)?.into())
+}
+
+/// Converts an integer into one or multiple letters.
+pub fn letter(_: &mut Vm, args: &mut Args) -> SourceResult<Value> {
+    numbered(Numbering::Letter, args)
+}
+
+/// Converts an integer into a roman numeral.
+pub fn roman(_: &mut Vm, args: &mut Args) -> SourceResult<Value> {
+    numbered(Numbering::Roman, args)
+}
+
+/// Convert a number into a symbol.
+pub fn symbol(_: &mut Vm, args: &mut Args) -> SourceResult<Value> {
+    numbered(Numbering::Symbol, args)
+}
+
+fn numbered(numbering: Numbering, args: &mut Args) -> SourceResult<Value> {
+    let n = args.expect::<usize>("non-negative integer")?;
+    Ok(Value::Str(numbering.apply(n).into()))
+}
+
+/// Allows to convert a number into letters, roman numerals and symbols.
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+pub enum Numbering {
+    Arabic,
+    Letter,
+    Roman,
+    Symbol,
+}
+
+impl Numbering {
+    /// Apply the numbering to the given number.
+    pub fn apply(self, mut n: usize) -> EcoString {
+        match self {
+            Self::Arabic => {
+                format_eco!("{}", n)
+            }
+            Self::Letter => {
+                if n == 0 {
+                    return '-'.into();
+                }
+
+                n -= 1;
+
+                let mut letters = vec![];
+                loop {
+                    letters.push(b'a' + (n % 26) as u8);
+                    n /= 26;
+                    if n == 0 {
+                        break;
+                    }
+                }
+
+                letters.reverse();
+                String::from_utf8(letters).unwrap().into()
+            }
+            Self::Roman => {
+                if n == 0 {
+                    return 'N'.into();
+                }
+
+                // Adapted from Yann Villessuzanne's roman.rs under the Unlicense, at
+                // https://github.com/linfir/roman.rs/
+                let mut fmt = EcoString::new();
+                for &(name, value) in ROMANS {
+                    while n >= value {
+                        n -= value;
+                        fmt.push_str(name);
+                    }
+                }
+
+                fmt
+            }
+            Self::Symbol => {
+                if n == 0 {
+                    return '-'.into();
+                }
+
+                let symbol = SYMBOLS[(n - 1) % SYMBOLS.len()];
+                let amount = ((n - 1) / SYMBOLS.len()) + 1;
+                std::iter::repeat(symbol).take(amount).collect()
+            }
+        }
+    }
+}
+
+const ROMANS: &[(&str, usize)] = &[
+    ("M̅", 1000000),
+    ("D̅", 500000),
+    ("C̅", 100000),
+    ("L̅", 50000),
+    ("X̅", 10000),
+    ("V̅", 5000),
+    ("I̅V̅", 4000),
+    ("M", 1000),
+    ("CM", 900),
+    ("D", 500),
+    ("CD", 400),
+    ("C", 100),
+    ("XC", 90),
+    ("L", 50),
+    ("XL", 40),
+    ("X", 10),
+    ("IX", 9),
+    ("V", 5),
+    ("IV", 4),
+    ("I", 1),
+];
+
+const SYMBOLS: &[char] = &['*', '†', '‡', '§', '‖', '¶'];