typst/library/src/compute/foundations.rs
2023-03-10 12:55:21 +01:00

132 lines
2.8 KiB
Rust

use crate::prelude::*;
/// Determine a value's type.
///
/// Returns the name of the value's type.
///
/// ## Example
/// ```example
/// #type(12) \
/// #type(14.7) \
/// #type("hello") \
/// #type(none) \
/// #type([Hi]) \
/// #type(x => x + 1)
/// ```
///
/// Display: Type
/// Category: foundations
/// Returns: string
#[func]
pub fn type_(
/// The value whose type's to determine.
value: Value,
) -> Value {
value.type_name().into()
}
/// The string representation of a value.
///
/// When inserted into content, most values are displayed as this representation
/// in monospace with syntax-highlighting. The exceptions are `{none}`,
/// integers, floats, strings, content, and functions.
///
/// ## Example
/// ```example
/// #none vs #repr(none) \
/// #"hello" vs #repr("hello") \
/// #(1, 2) vs #repr((1, 2)) \
/// #[*Hi*] vs #repr([*Hi*])
/// ```
///
/// Display: Representation
/// Category: foundations
/// Returns: string
#[func]
pub fn repr(
/// The value whose string representation to produce.
value: Value,
) -> Value {
value.repr().into()
}
/// Fail with an error.
///
/// ## Example
/// The code below produces the error `panicked at: "this is wrong"`.
/// ```typ
/// #panic("this is wrong")
/// ```
///
/// Display: Panic
/// Category: foundations
/// Returns:
#[func]
pub fn panic(
/// The value (or message) to panic with.
#[default]
payload: Option<Value>,
) -> Value {
match payload {
Some(v) => bail!(args.span, "panicked with: {}", v.repr()),
None => bail!(args.span, "panicked"),
}
}
/// Ensure that a condition is fulfilled.
///
/// Fails with an error if the condition is not fulfilled. Does not
/// produce any output in the document.
///
/// ## Example
/// ```typ
/// #assert(1 < 2, message: "math broke")
/// ```
///
/// Display: Assert
/// Category: foundations
/// Returns:
#[func]
pub fn assert(
/// The condition that must be true for the assertion to pass.
condition: bool,
/// The error message when the assertion fails.
#[named]
#[default]
message: Option<EcoString>,
) -> Value {
if !condition {
if let Some(message) = message {
bail!(args.span, "assertion failed: {}", message);
} else {
bail!(args.span, "assertion failed");
}
}
Value::None
}
/// Evaluate a string as Typst code.
///
/// This function should only be used as a last resort.
///
/// ## Example
/// ```example
/// #eval("1 + 1") \
/// #eval("(1, 2, 3, 4)").len() \
/// #eval("[*Strong text*]")
/// ```
///
/// Display: Evaluate
/// Category: foundations
/// Returns: any
#[func]
pub fn eval(
/// A string of Typst code to evaluate.
///
/// The code in the string cannot interact with the file system.
source: Spanned<String>,
) -> Value {
let Spanned { v: text, span } = source;
typst::eval::eval_code_str(vm.world(), &text, span)?
}