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Diffstat (limited to 'tvix/eval/src/builtins/mod.rs')
| -rw-r--r-- | tvix/eval/src/builtins/mod.rs | 1060 |
1 files changed, 1060 insertions, 0 deletions
diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs new file mode 100644 index 000000000000..13355fa1c5d2 --- /dev/null +++ b/tvix/eval/src/builtins/mod.rs @@ -0,0 +1,1060 @@ +//! This module implements the builtins exposed in the Nix language. +//! +//! See //tvix/eval/docs/builtins.md for a some context on the +//! available builtins in Nix. + +use builtin_macros::builtins; +use genawaiter::rc::Gen; +use regex::Regex; +use std::cmp::{self, Ordering}; +use std::collections::VecDeque; +use std::collections::{BTreeMap, HashSet}; +use std::path::PathBuf; + +use crate::arithmetic_op; +use crate::value::PointerEquality; +use crate::vm::generators::{self, GenCo}; +use crate::warnings::WarningKind; +use crate::{ + self as tvix_eval, + errors::{CatchableErrorKind, ErrorKind}, + value::{CoercionKind, NixAttrs, NixList, NixString, SharedThunkSet, Thunk, Value}, +}; + +use self::versions::{VersionPart, VersionPartsIter}; + +mod to_xml; +mod versions; + +#[cfg(feature = "impure")] +mod impure; + +#[cfg(feature = "impure")] +pub use impure::impure_builtins; + +// we set TVIX_CURRENT_SYSTEM in build.rs +pub const CURRENT_PLATFORM: &str = env!("TVIX_CURRENT_SYSTEM"); + +/// Coerce a Nix Value to a plain path, e.g. in order to access the +/// file it points to via either `builtins.toPath` or an impure +/// builtin. This coercion can _never_ be performed in a Nix program +/// without using builtins (i.e. the trick `path: /. + path` to +/// convert from a string to a path wouldn't hit this code). +pub async fn coerce_value_to_path( + co: &GenCo, + v: Value, +) -> Result<Result<PathBuf, CatchableErrorKind>, ErrorKind> { + let value = generators::request_force(co, v).await; + if let Value::Path(p) = value { + return Ok(Ok(*p)); + } + + match generators::request_string_coerce(co, value, CoercionKind::Weak).await { + Ok(vs) => { + let path = PathBuf::from(vs.as_str()); + if path.is_absolute() { + Ok(Ok(path)) + } else { + Err(ErrorKind::NotAnAbsolutePath(path)) + } + } + Err(cek) => Ok(Err(cek)), + } +} + +#[builtins] +mod pure_builtins { + use crate::value::PointerEquality; + + use super::*; + + #[builtin("abort")] + async fn builtin_abort(co: GenCo, message: Value) -> Result<Value, ErrorKind> { + Err(ErrorKind::Abort(message.to_str()?.to_string())) + } + + #[builtin("add")] + async fn builtin_add(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + arithmetic_op!(&x, &y, +) + } + + #[builtin("all")] + async fn builtin_all(co: GenCo, pred: Value, list: Value) -> Result<Value, ErrorKind> { + for value in list.to_list()?.into_iter() { + let pred_result = generators::request_call_with(&co, pred.clone(), [value]).await; + let pred_result = generators::request_force(&co, pred_result).await; + + if !pred_result.as_bool()? { + return Ok(Value::Bool(false)); + } + } + + Ok(Value::Bool(true)) + } + + #[builtin("any")] + async fn builtin_any(co: GenCo, pred: Value, list: Value) -> Result<Value, ErrorKind> { + for value in list.to_list()?.into_iter() { + let pred_result = generators::request_call_with(&co, pred.clone(), [value]).await; + let pred_result = generators::request_force(&co, pred_result).await; + + if pred_result.as_bool()? { + return Ok(Value::Bool(true)); + } + } + + Ok(Value::Bool(false)) + } + + #[builtin("attrNames")] + async fn builtin_attr_names(co: GenCo, set: Value) -> Result<Value, ErrorKind> { + let xs = set.to_attrs()?; + let mut output = Vec::with_capacity(xs.len()); + + for (key, _val) in xs.iter() { + output.push(Value::String(key.clone())); + } + + Ok(Value::List(NixList::construct(output.len(), output))) + } + + #[builtin("attrValues")] + async fn builtin_attr_values(co: GenCo, set: Value) -> Result<Value, ErrorKind> { + let xs = set.to_attrs()?; + let mut output = Vec::with_capacity(xs.len()); + + for (_key, val) in xs.iter() { + output.push(val.clone()); + } + + Ok(Value::List(NixList::construct(output.len(), output))) + } + + #[builtin("baseNameOf")] + async fn builtin_base_name_of(co: GenCo, s: Value) -> Result<Value, ErrorKind> { + let s = s.coerce_to_string(co, CoercionKind::Weak).await?.to_str()?; + let result: String = s.rsplit_once('/').map(|(_, x)| x).unwrap_or(&s).into(); + Ok(result.into()) + } + + #[builtin("bitAnd")] + async fn builtin_bit_and(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + Ok(Value::Integer(x.as_int()? & y.as_int()?)) + } + + #[builtin("bitOr")] + async fn builtin_bit_or(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + Ok(Value::Integer(x.as_int()? | y.as_int()?)) + } + + #[builtin("bitXor")] + async fn builtin_bit_xor(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + Ok(Value::Integer(x.as_int()? ^ y.as_int()?)) + } + + #[builtin("catAttrs")] + async fn builtin_cat_attrs(co: GenCo, key: Value, list: Value) -> Result<Value, ErrorKind> { + let key = key.to_str()?; + let list = list.to_list()?; + let mut output = vec![]; + + for item in list.into_iter() { + let set = generators::request_force(&co, item).await.to_attrs()?; + + if let Some(value) = set.select(key.as_str()) { + output.push(value.clone()); + } + } + + Ok(Value::List(NixList::construct(output.len(), output))) + } + + #[builtin("ceil")] + async fn builtin_ceil(co: GenCo, double: Value) -> Result<Value, ErrorKind> { + Ok(Value::Integer(double.as_float()?.ceil() as i64)) + } + + #[builtin("compareVersions")] + async fn builtin_compare_versions(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + let s1 = x.to_str()?; + let s1 = VersionPartsIter::new_for_cmp(s1.as_str()); + let s2 = y.to_str()?; + let s2 = VersionPartsIter::new_for_cmp(s2.as_str()); + + match s1.cmp(s2) { + std::cmp::Ordering::Less => Ok(Value::Integer(-1)), + std::cmp::Ordering::Equal => Ok(Value::Integer(0)), + std::cmp::Ordering::Greater => Ok(Value::Integer(1)), + } + } + + #[builtin("concatLists")] + async fn builtin_concat_lists(co: GenCo, lists: Value) -> Result<Value, ErrorKind> { + let mut out = imbl::Vector::new(); + + for value in lists.to_list()? { + let list = generators::request_force(&co, value).await.to_list()?; + out.extend(list.into_iter()); + } + + Ok(Value::List(out.into())) + } + + #[builtin("concatMap")] + async fn builtin_concat_map(co: GenCo, f: Value, list: Value) -> Result<Value, ErrorKind> { + let list = list.to_list()?; + let mut res = imbl::Vector::new(); + for val in list { + let out = generators::request_call_with(&co, f.clone(), [val]).await; + let out = generators::request_force(&co, out).await; + res.extend(out.to_list()?); + } + Ok(Value::List(res.into())) + } + + #[builtin("concatStringsSep")] + async fn builtin_concat_strings_sep( + co: GenCo, + separator: Value, + list: Value, + ) -> Result<Value, ErrorKind> { + let separator = separator.to_str()?; + let list = list.to_list()?; + let mut res = String::new(); + for (i, val) in list.into_iter().enumerate() { + if i != 0 { + res.push_str(&separator); + } + match generators::request_string_coerce(&co, val, CoercionKind::Weak).await { + Ok(s) => res.push_str(s.as_str()), + Err(c) => return Ok(Value::Catchable(c)), + } + } + Ok(res.into()) + } + + #[builtin("deepSeq")] + async fn builtin_deep_seq(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + generators::request_deep_force(&co, x, SharedThunkSet::default()).await; + Ok(y) + } + + #[builtin("div")] + async fn builtin_div(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + arithmetic_op!(&x, &y, /) + } + + #[builtin("dirOf")] + async fn builtin_dir_of(co: GenCo, s: Value) -> Result<Value, ErrorKind> { + let is_path = s.is_path(); + let str = s.coerce_to_string(co, CoercionKind::Weak).await?.to_str()?; + let result = str + .rsplit_once('/') + .map(|(x, _)| match x { + "" => "/", + _ => x, + }) + .unwrap_or("."); + if is_path { + Ok(Value::Path(Box::new(result.into()))) + } else { + Ok(result.into()) + } + } + + #[builtin("elem")] + async fn builtin_elem(co: GenCo, x: Value, xs: Value) -> Result<Value, ErrorKind> { + for val in xs.to_list()? { + if generators::check_equality(&co, x.clone(), val, PointerEquality::AllowAll).await? { + return Ok(true.into()); + } + } + Ok(false.into()) + } + + #[builtin("elemAt")] + async fn builtin_elem_at(co: GenCo, xs: Value, i: Value) -> Result<Value, ErrorKind> { + let xs = xs.to_list()?; + let i = i.as_int()?; + if i < 0 { + Err(ErrorKind::IndexOutOfBounds { index: i }) + } else { + match xs.get(i as usize) { + Some(x) => Ok(x.clone()), + None => Err(ErrorKind::IndexOutOfBounds { index: i }), + } + } + } + + #[builtin("filter")] + async fn builtin_filter(co: GenCo, pred: Value, list: Value) -> Result<Value, ErrorKind> { + let list: NixList = list.to_list()?; + let mut out = imbl::Vector::new(); + + for value in list { + let result = generators::request_call_with(&co, pred.clone(), [value.clone()]).await; + + if generators::request_force(&co, result).await.as_bool()? { + out.push_back(value); + } + } + + Ok(Value::List(out.into())) + } + + #[builtin("floor")] + async fn builtin_floor(co: GenCo, double: Value) -> Result<Value, ErrorKind> { + Ok(Value::Integer(double.as_float()?.floor() as i64)) + } + + #[builtin("foldl'")] + async fn builtin_foldl( + co: GenCo, + op: Value, + #[lazy] nul: Value, + list: Value, + ) -> Result<Value, ErrorKind> { + let mut nul = nul; + let list = list.to_list()?; + for val in list { + // Every call of `op` is forced immediately, but `nul` is not, see + // https://github.com/NixOS/nix/blob/940e9eb8/src/libexpr/primops.cc#L3069-L3070C36 + // and our tests for foldl'. + nul = generators::request_call_with(&co, op.clone(), [nul, val]).await; + nul = generators::request_force(&co, nul).await; + if let c @ Value::Catchable(_) = nul { + return Ok(c); + } + } + + Ok(nul) + } + + #[builtin("functionArgs")] + async fn builtin_function_args(co: GenCo, f: Value) -> Result<Value, ErrorKind> { + let lambda = &f.as_closure()?.lambda(); + let formals = if let Some(formals) = &lambda.formals { + formals + } else { + return Ok(Value::attrs(NixAttrs::empty())); + }; + Ok(Value::attrs(NixAttrs::from_iter( + formals.arguments.iter().map(|(k, v)| (k.clone(), (*v))), + ))) + } + + #[builtin("fromJSON")] + async fn builtin_from_json(co: GenCo, json: Value) -> Result<Value, ErrorKind> { + let json_str = json.to_str()?; + + serde_json::from_str(&json_str).map_err(|err| err.into()) + } + + #[builtin("toJSON")] + async fn builtin_to_json(co: GenCo, val: Value) -> Result<Value, ErrorKind> { + match val.to_json(&co).await? { + Err(cek) => Ok(Value::Catchable(cek)), + Ok(json_value) => { + let json_str = serde_json::to_string(&json_value)?; + Ok(json_str.into()) + } + } + } + + #[builtin("fromTOML")] + async fn builtin_from_toml(co: GenCo, toml: Value) -> Result<Value, ErrorKind> { + let toml_str = toml.to_str()?; + + toml::from_str(&toml_str).map_err(|err| err.into()) + } + + #[builtin("genericClosure")] + async fn builtin_generic_closure(co: GenCo, input: Value) -> Result<Value, ErrorKind> { + let attrs = input.to_attrs()?; + + // The work set is maintained as a VecDeque because new items + // are popped from the front. + let mut work_set: VecDeque<Value> = + generators::request_force(&co, attrs.select_required("startSet")?.clone()) + .await + .to_list()? + .into_iter() + .collect(); + + let operator = attrs.select_required("operator")?; + + let mut res = imbl::Vector::new(); + let mut done_keys: Vec<Value> = vec![]; + + while let Some(val) = work_set.pop_front() { + let val = generators::request_force(&co, val).await; + let attrs = val.to_attrs()?; + let key = attrs.select_required("key")?; + + if !bgc_insert_key(&co, key.clone(), &mut done_keys).await? { + continue; + } + + res.push_back(val.clone()); + + let op_result = generators::request_force( + &co, + generators::request_call_with(&co, operator.clone(), [val]).await, + ) + .await; + + work_set.extend(op_result.to_list()?.into_iter()); + } + + Ok(Value::List(NixList::from(res))) + } + + #[builtin("genList")] + async fn builtin_gen_list( + co: GenCo, + generator: Value, + length: Value, + ) -> Result<Value, ErrorKind> { + let mut out = imbl::Vector::<Value>::new(); + let len = length.as_int()?; + // the best span we can get… + let span = generators::request_span(&co).await; + + for i in 0..len { + let val = Value::Thunk(Thunk::new_suspended_call( + generator.clone(), + i.into(), + span.clone(), + )); + out.push_back(val); + } + + Ok(Value::List(out.into())) + } + + #[builtin("getAttr")] + async fn builtin_get_attr(co: GenCo, key: Value, set: Value) -> Result<Value, ErrorKind> { + let k = key.to_str()?; + let xs = set.to_attrs()?; + + match xs.select(k.as_str()) { + Some(x) => Ok(x.clone()), + None => Err(ErrorKind::AttributeNotFound { + name: k.to_string(), + }), + } + } + + #[builtin("groupBy")] + async fn builtin_group_by(co: GenCo, f: Value, list: Value) -> Result<Value, ErrorKind> { + let mut res: BTreeMap<NixString, imbl::Vector<Value>> = BTreeMap::new(); + for val in list.to_list()? { + let key = generators::request_force( + &co, + generators::request_call_with(&co, f.clone(), [val.clone()]).await, + ) + .await + .to_str()?; + + res.entry(key) + .or_insert_with(imbl::Vector::new) + .push_back(val); + } + Ok(Value::attrs(NixAttrs::from_iter( + res.into_iter() + .map(|(k, v)| (k, Value::List(NixList::from(v)))), + ))) + } + + #[builtin("hasAttr")] + async fn builtin_has_attr(co: GenCo, key: Value, set: Value) -> Result<Value, ErrorKind> { + let k = key.to_str()?; + let xs = set.to_attrs()?; + + Ok(Value::Bool(xs.contains(k.as_str()))) + } + + #[builtin("head")] + async fn builtin_head(co: GenCo, list: Value) -> Result<Value, ErrorKind> { + match list.to_list()?.get(0) { + Some(x) => Ok(x.clone()), + None => Err(ErrorKind::IndexOutOfBounds { index: 0 }), + } + } + + #[builtin("intersectAttrs")] + async fn builtin_intersect_attrs(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + let attrs1 = x.to_attrs()?; + let attrs2 = y.to_attrs()?; + let res = attrs2.iter().filter_map(|(k, v)| { + if attrs1.contains(k) { + Some((k.clone(), v.clone())) + } else { + None + } + }); + Ok(Value::attrs(NixAttrs::from_iter(res))) + } + + #[builtin("isAttrs")] + async fn builtin_is_attrs(co: GenCo, value: Value) -> Result<Value, ErrorKind> { + Ok(Value::Bool(matches!(value, Value::Attrs(_)))) + } + + #[builtin("isBool")] + async fn builtin_is_bool(co: GenCo, value: Value) -> Result<Value, ErrorKind> { + Ok(Value::Bool(matches!(value, Value::Bool(_)))) + } + + #[builtin("isFloat")] + async fn builtin_is_float(co: GenCo, value: Value) -> Result<Value, ErrorKind> { + Ok(Value::Bool(matches!(value, Value::Float(_)))) + } + + #[builtin("isFunction")] + async fn builtin_is_function(co: GenCo, value: Value) -> Result<Value, ErrorKind> { + Ok(Value::Bool(matches!( + value, + Value::Closure(_) | Value::Builtin(_) + ))) + } + + #[builtin("isInt")] + async fn builtin_is_int(co: GenCo, value: Value) -> Result<Value, ErrorKind> { + Ok(Value::Bool(matches!(value, Value::Integer(_)))) + } + + #[builtin("isList")] + async fn builtin_is_list(co: GenCo, value: Value) -> Result<Value, ErrorKind> { + Ok(Value::Bool(matches!(value, Value::List(_)))) + } + + #[builtin("isNull")] + async fn builtin_is_null(co: GenCo, value: Value) -> Result<Value, ErrorKind> { + Ok(Value::Bool(matches!(value, Value::Null))) + } + + #[builtin("isPath")] + async fn builtin_is_path(co: GenCo, value: Value) -> Result<Value, ErrorKind> { + Ok(Value::Bool(matches!(value, Value::Path(_)))) + } + + #[builtin("isString")] + async fn builtin_is_string(co: GenCo, value: Value) -> Result<Value, ErrorKind> { + Ok(Value::Bool(matches!(value, Value::String(_)))) + } + + #[builtin("length")] + async fn builtin_length(co: GenCo, list: Value) -> Result<Value, ErrorKind> { + Ok(Value::Integer(list.to_list()?.len() as i64)) + } + + #[builtin("lessThan")] + async fn builtin_less_than(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + Ok(Value::Bool(matches!( + x.nix_cmp_ordering(y, co).await?, + Some(Ordering::Less) + ))) + } + + #[builtin("listToAttrs")] + async fn builtin_list_to_attrs(co: GenCo, list: Value) -> Result<Value, ErrorKind> { + let list = list.to_list()?; + let mut map = BTreeMap::new(); + for val in list { + let attrs = generators::request_force(&co, val).await.to_attrs()?; + let name = generators::request_force(&co, attrs.select_required("name")?.clone()) + .await + .to_str()?; + let value = attrs.select_required("value")?.clone(); + // Map entries earlier in the list take precedence over entries later in the list + map.entry(name).or_insert(value); + } + Ok(Value::attrs(NixAttrs::from_iter(map.into_iter()))) + } + + #[builtin("map")] + async fn builtin_map(co: GenCo, f: Value, list: Value) -> Result<Value, ErrorKind> { + let mut out = imbl::Vector::<Value>::new(); + + // the best span we can get… + let span = generators::request_span(&co).await; + + for val in list.to_list()? { + let result = Value::Thunk(Thunk::new_suspended_call(f.clone(), val, span.clone())); + out.push_back(result) + } + + Ok(Value::List(out.into())) + } + + #[builtin("mapAttrs")] + async fn builtin_map_attrs(co: GenCo, f: Value, attrs: Value) -> Result<Value, ErrorKind> { + let attrs = attrs.to_attrs()?; + let mut out = imbl::OrdMap::new(); + + // the best span we can get… + let span = generators::request_span(&co).await; + + for (key, value) in attrs.into_iter() { + let result = Value::Thunk(Thunk::new_suspended_call( + f.clone(), + key.clone().into(), + span.clone(), + )); + let result = Value::Thunk(Thunk::new_suspended_call(result, value, span.clone())); + + out.insert(key, result); + } + + Ok(Value::attrs(out.into())) + } + + #[builtin("match")] + async fn builtin_match(co: GenCo, regex: Value, str: Value) -> Result<Value, ErrorKind> { + let s = str.to_str()?; + let re = regex.to_str()?; + let re: Regex = Regex::new(&format!("^{}$", re.as_str())).unwrap(); + match re.captures(&s) { + Some(caps) => Ok(Value::List( + caps.iter() + .skip(1) + .map(|grp| grp.map(|g| Value::from(g.as_str())).unwrap_or(Value::Null)) + .collect::<imbl::Vector<Value>>() + .into(), + )), + None => Ok(Value::Null), + } + } + + #[builtin("mul")] + async fn builtin_mul(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + arithmetic_op!(&x, &y, *) + } + + #[builtin("parseDrvName")] + async fn builtin_parse_drv_name(co: GenCo, s: Value) -> Result<Value, ErrorKind> { + // This replicates cppnix's (mis?)handling of codepoints + // above U+007f following 0x2d ('-') + let s = s.to_str()?; + let slice: &[u8] = s.as_str().as_ref(); + let (name, dash_and_version) = slice.split_at( + slice + .windows(2) + .enumerate() + .find_map(|x| match x { + (idx, [b'-', c1]) if !c1.is_ascii_alphabetic() => Some(idx), + _ => None, + }) + .unwrap_or(slice.len()), + ); + let version = dash_and_version + .split_first() + .map(|x| core::str::from_utf8(x.1)) + .unwrap_or(Ok(""))?; + Ok(Value::attrs(NixAttrs::from_iter( + [("name", core::str::from_utf8(name)?), ("version", version)].into_iter(), + ))) + } + + #[builtin("partition")] + async fn builtin_partition(co: GenCo, pred: Value, list: Value) -> Result<Value, ErrorKind> { + let mut right: imbl::Vector<Value> = Default::default(); + let mut wrong: imbl::Vector<Value> = Default::default(); + + let list: NixList = list.to_list()?; + for elem in list { + let result = generators::request_call_with(&co, pred.clone(), [elem.clone()]).await; + + if generators::request_force(&co, result).await.as_bool()? { + right.push_back(elem); + } else { + wrong.push_back(elem); + }; + } + + let res = [ + ("right", Value::List(NixList::from(right))), + ("wrong", Value::List(NixList::from(wrong))), + ]; + + Ok(Value::attrs(NixAttrs::from_iter(res.into_iter()))) + } + + #[builtin("removeAttrs")] + async fn builtin_remove_attrs( + co: GenCo, + attrs: Value, + keys: Value, + ) -> Result<Value, ErrorKind> { + let attrs = attrs.to_attrs()?; + let keys = keys + .to_list()? + .into_iter() + .map(|v| v.to_str()) + .collect::<Result<HashSet<_>, _>>()?; + let res = attrs.iter().filter_map(|(k, v)| { + if !keys.contains(k) { + Some((k.clone(), v.clone())) + } else { + None + } + }); + Ok(Value::attrs(NixAttrs::from_iter(res))) + } + + #[builtin("replaceStrings")] + async fn builtin_replace_strings( + co: GenCo, + from: Value, + to: Value, + s: Value, + ) -> Result<Value, ErrorKind> { + let from = from.to_list()?; + for val in &from { + generators::request_force(&co, val.clone()).await; + } + + let to = to.to_list()?; + for val in &to { + generators::request_force(&co, val.clone()).await; + } + + let string = s.to_str()?; + + let mut res = String::new(); + + let mut i: usize = 0; + let mut empty_string_replace = false; + + // This can't be implemented using Rust's string.replace() as + // well as a map because we need to handle errors with results + // as well as "reset" the iterator to zero for the replacement + // everytime there's a successful match. + // Also, Rust's string.replace allocates a new string + // on every call which is not preferable. + 'outer: while i < string.len() { + // Try a match in all the from strings + for elem in std::iter::zip(from.iter(), to.iter()) { + let from = elem.0.to_str()?; + let to = elem.1.to_str()?; + + if i + from.len() > string.len() { + continue; + } + + // We already applied a from->to with an empty from + // transformation. + // Let's skip it so that we don't loop infinitely + if empty_string_replace && from.as_str().is_empty() { + continue; + } + + // if we match the `from` string, let's replace + if &string[i..i + from.len()] == from.as_str() { + res += &to; + i += from.len(); + + // remember if we applied the empty from->to + empty_string_replace = from.as_str().is_empty(); + + continue 'outer; + } + } + + // If we don't match any `from`, we simply add a character + res += &string[i..i + 1]; + i += 1; + + // Since we didn't apply anything transformation, + // we reset the empty string replacement + empty_string_replace = false; + } + + // Special case when the string is empty or at the string's end + // and one of the from is also empty + for elem in std::iter::zip(from.iter(), to.iter()) { + let from = elem.0.to_str()?; + let to = elem.1.to_str()?; + + if from.as_str().is_empty() { + res += &to; + break; + } + } + Ok(Value::String(res.into())) + } + + #[builtin("seq")] + async fn builtin_seq(co: GenCo, _x: Value, y: Value) -> Result<Value, ErrorKind> { + // The builtin calling infra has already forced both args for us, so + // we just return the second and ignore the first + Ok(y) + } + + #[builtin("split")] + async fn builtin_split(co: GenCo, regex: Value, str: Value) -> Result<Value, ErrorKind> { + let s = str.to_str()?; + let text = s.as_str(); + let re = regex.to_str()?; + let re: Regex = Regex::new(re.as_str()).unwrap(); + let mut capture_locations = re.capture_locations(); + let num_captures = capture_locations.len(); + let mut ret = imbl::Vector::new(); + let mut pos = 0; + + while let Some(thematch) = re.captures_read_at(&mut capture_locations, text, pos) { + // push the unmatched characters preceding the match + ret.push_back(Value::from(&text[pos..thematch.start()])); + + // Push a list with one element for each capture + // group in the regex, containing the characters + // matched by that capture group, or null if no match. + // We skip capture 0; it represents the whole match. + let v: imbl::Vector<Value> = (1..num_captures) + .map(|i| capture_locations.get(i)) + .map(|o| { + o.map(|(start, end)| Value::from(&text[start..end])) + .unwrap_or(Value::Null) + }) + .collect(); + ret.push_back(Value::List(NixList::from(v))); + pos = thematch.end(); + } + + // push the unmatched characters following the last match + ret.push_back(Value::from(&text[pos..])); + + Ok(Value::List(NixList::from(ret))) + } + + #[builtin("sort")] + async fn builtin_sort(co: GenCo, comparator: Value, list: Value) -> Result<Value, ErrorKind> { + let list = list.to_list()?; + let sorted = list.sort_by(&co, comparator).await?; + Ok(Value::List(sorted)) + } + + #[builtin("splitVersion")] + async fn builtin_split_version(co: GenCo, s: Value) -> Result<Value, ErrorKind> { + let s = s.to_str()?; + let s = VersionPartsIter::new(s.as_str()); + + let parts = s + .map(|s| { + Value::String(match s { + VersionPart::Number(n) => n.into(), + VersionPart::Word(w) => w.into(), + }) + }) + .collect::<Vec<Value>>(); + Ok(Value::List(NixList::construct(parts.len(), parts))) + } + + #[builtin("stringLength")] + async fn builtin_string_length(co: GenCo, #[lazy] s: Value) -> Result<Value, ErrorKind> { + // also forces the value + let s = s.coerce_to_string(co, CoercionKind::Weak).await?; + Ok(Value::Integer(s.to_str()?.as_str().len() as i64)) + } + + #[builtin("sub")] + async fn builtin_sub(co: GenCo, x: Value, y: Value) -> Result<Value, ErrorKind> { + arithmetic_op!(&x, &y, -) + } + + #[builtin("substring")] + async fn builtin_substring( + co: GenCo, + start: Value, + len: Value, + s: Value, + ) -> Result<Value, ErrorKind> { + let beg = start.as_int()?; + let len = len.as_int()?; + let x = s.coerce_to_string(co, CoercionKind::Weak).await?.to_str()?; + + if beg < 0 { + return Err(ErrorKind::IndexOutOfBounds { index: beg }); + } + let beg = beg as usize; + + // Nix doesn't assert that the length argument is + // non-negative when the starting index is GTE the + // string's length. + if beg >= x.as_str().len() { + return Ok(Value::String("".into())); + } + + let end = if len < 0 { + x.as_str().len() + } else { + cmp::min(beg + (len as usize), x.as_str().len()) + }; + + Ok(Value::String(x.as_str()[beg..end].into())) + } + + #[builtin("tail")] + async fn builtin_tail(co: GenCo, list: Value) -> Result<Value, ErrorKind> { + let xs = list.to_list()?; + + if xs.is_empty() { + Err(ErrorKind::TailEmptyList) + } else { + let output = xs.into_iter().skip(1).collect::<Vec<_>>(); + Ok(Value::List(NixList::construct(output.len(), output))) + } + } + + #[builtin("throw")] + async fn builtin_throw(co: GenCo, message: Value) -> Result<Value, ErrorKind> { + Ok(Value::Catchable(CatchableErrorKind::Throw( + message.to_str()?.to_string(), + ))) + } + + #[builtin("toString")] + async fn builtin_to_string(co: GenCo, #[lazy] x: Value) -> Result<Value, ErrorKind> { + // coerce_to_string forces for us + x.coerce_to_string(co, CoercionKind::Strong).await + } + + #[builtin("toXML")] + async fn builtin_to_xml(co: GenCo, value: Value) -> Result<Value, ErrorKind> { + let value = generators::request_deep_force(&co, value, SharedThunkSet::default()).await; + let mut buf: Vec<u8> = vec![]; + to_xml::value_to_xml(&mut buf, &value)?; + Ok(String::from_utf8(buf)?.into()) + } + + #[builtin("placeholder")] + async fn builtin_placeholder(co: GenCo, #[lazy] _x: Value) -> Result<Value, ErrorKind> { + generators::emit_warning_kind(&co, WarningKind::NotImplemented("builtins.placeholder")) + .await; + Ok("<builtins.placeholder-is-not-implemented-in-tvix-yet>".into()) + } + + #[builtin("trace")] + async fn builtin_trace(co: GenCo, message: Value, value: Value) -> Result<Value, ErrorKind> { + // TODO(grfn): `trace` should be pluggable and capturable, probably via a method on + // the VM + eprintln!("trace: {} :: {}", message, message.type_of()); + Ok(value) + } + + #[builtin("toPath")] + async fn builtin_to_path(co: GenCo, s: Value) -> Result<Value, ErrorKind> { + match coerce_value_to_path(&co, s).await? { + Err(cek) => return Ok(Value::Catchable(cek)), + Ok(path) => { + let path: Value = crate::value::canon_path(path).into(); + Ok(path.coerce_to_string(co, CoercionKind::Weak).await?) + } + } + } + + #[builtin("tryEval")] + async fn builtin_try_eval(co: GenCo, #[lazy] e: Value) -> Result<Value, ErrorKind> { + let res = match generators::request_try_force(&co, e).await { + Value::Catchable(_) => [("value", false.into()), ("success", false.into())], + value => [("value", value), ("success", true.into())], + }; + + Ok(Value::attrs(NixAttrs::from_iter(res.into_iter()))) + } + + #[builtin("typeOf")] + async fn builtin_type_of(co: GenCo, x: Value) -> Result<Value, ErrorKind> { + Ok(Value::String(x.type_of().into())) + } +} + +/// Internal helper function for genericClosure, determining whether a +/// value has been seen before. +async fn bgc_insert_key(co: &GenCo, key: Value, done: &mut Vec<Value>) -> Result<bool, ErrorKind> { + for existing in done.iter() { + if generators::check_equality( + co, + existing.clone(), + key.clone(), + // TODO(tazjin): not actually sure which semantics apply here + PointerEquality::ForbidAll, + ) + .await? + { + return Ok(false); + } + } + + done.push(key); + Ok(true) +} + +/// The set of standard pure builtins in Nix, mostly concerned with +/// data structure manipulation (string, attrs, list, etc. functions). +pub fn pure_builtins() -> Vec<(&'static str, Value)> { + let mut result = pure_builtins::builtins(); + + // Pure-value builtins + result.push(("nixVersion", Value::String("2.3-compat-tvix-0.1".into()))); + result.push(("langVersion", Value::Integer(6))); + result.push(("null", Value::Null)); + result.push(("true", Value::Bool(true))); + result.push(("false", Value::Bool(false))); + + result.push(( + "currentSystem", + crate::systems::llvm_triple_to_nix_double(CURRENT_PLATFORM).into(), + )); + + result +} + +#[builtins] +mod placeholder_builtins { + use super::*; + + #[builtin("unsafeDiscardStringContext")] + async fn builtin_unsafe_discard_string_context( + _: GenCo, + #[lazy] s: Value, + ) -> Result<Value, ErrorKind> { + // Tvix does not manually track contexts, and this is a no-op for us. + Ok(s) + } + + #[builtin("addErrorContext")] + async fn builtin_add_error_context( + co: GenCo, + #[lazy] _context: Value, + #[lazy] val: Value, + ) -> Result<Value, ErrorKind> { + generators::emit_warning_kind(&co, WarningKind::NotImplemented("builtins.addErrorContext")) + .await; + Ok(val) + } + + #[builtin("unsafeGetAttrPos")] + async fn builtin_unsafe_get_attr_pos( + co: GenCo, + _name: Value, + _attrset: Value, + ) -> Result<Value, ErrorKind> { + generators::emit_warning_kind( + &co, + WarningKind::NotImplemented("builtins.unsafeGetAttrsPos"), + ) + .await; + let res = [ + ("line", 42.into()), + ("col", 42.into()), + ("file", Value::Path(Box::new("/deep/thought".into()))), + ]; + Ok(Value::attrs(NixAttrs::from_iter(res.into_iter()))) + } +} + +pub fn placeholders() -> Vec<(&'static str, Value)> { + placeholder_builtins::builtins() +} |