5 files changed, 63 insertions, 0 deletions
diff --git a/tvix/eval/Cargo.lock b/tvix/eval/Cargo.lock
index b9fa3d3a11da..5e9aaa08679b 100644
--- a/tvix/eval/Cargo.lock
+++ b/tvix/eval/Cargo.lock
@@ -3,6 +3,15 @@
 version = 3
 
 [[package]]
+name = "aho-corasick"
+version = "0.7.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4f55bd91a0978cbfd91c457a164bab8b4001c833b7f323132c0a4e1922dd44e"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
 name = "atty"
 version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -859,6 +868,8 @@ version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4c4eb3267174b8c6c2f654116623910a0fef09c4753f8dd83db29c48a0df988b"
 dependencies = [
+ "aho-corasick",
+ "memchr",
  "regex-syntax",
 ]
 
@@ -1208,6 +1219,7 @@ dependencies = [
  "path-clean",
  "pretty_assertions",
  "proptest",
+ "regex",
  "rnix",
  "rowan",
  "rustyline",
diff --git a/tvix/eval/Cargo.toml b/tvix/eval/Cargo.toml
index 67ed42609deb..3c6213c21520 100644
--- a/tvix/eval/Cargo.toml
+++ b/tvix/eval/Cargo.toml
@@ -25,6 +25,7 @@ proptest = { version = "1.0.0", default_features = false, features = ["std", "al
 test-strategy = { version = "0.2.1", optional = true }
 clap = { version = "3.2.22", optional = true, features = ["derive", "env"] }
 serde_json = "1.0.86"
+regex = "1.6.0"
 
 # rnix has not been released in a while (as of 2022-09-23), we will
 # use it from git.
diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs
index c0dce868c6fc..0082d36d5735 100644
--- a/tvix/eval/src/builtins/mod.rs
+++ b/tvix/eval/src/builtins/mod.rs
@@ -7,6 +7,8 @@ use std::cmp;
 use std::collections::{BTreeMap, HashMap, HashSet};
 use std::path::PathBuf;
 
+use regex::Regex;
+
 use crate::{
     errors::ErrorKind,
     value::{Builtin, CoercionKind, NixAttrs, NixList, NixString, Value},
@@ -382,6 +384,24 @@ fn pure_builtins() -> Vec<Builtin> {
                 .map_err(Into::into)
         }),
         Builtin::new(
+            "match",
+            &[true, true],
+            |mut args: Vec<Value>, _: &mut VM| {
+                let s = args.pop().unwrap().to_str()?;
+                let re = args.pop().unwrap().to_str()?;
+                let re: Regex = Regex::new(&format!("^{}$", re.as_str())).unwrap();
+                match re.captures(&s) {
+                    Some(caps) => Ok(caps
+                        .iter()
+                        .skip(1)
+                        .map(|grp| grp.map(|g| Value::from(g.as_str())).unwrap_or(Value::Null))
+                        .collect::<Vec<Value>>()
+                        .into()),
+                    None => Ok(Value::Null),
+                }
+            },
+        ),
+        Builtin::new(
             "mul",
             &[false, false],
             |args: Vec<Value>, vm: &mut VM| arithmetic_op!(&*args[0].force(vm)?, &*args[1].force(vm)?, *),
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-regex-match.exp b/tvix/eval/src/tests/tvix_tests/eval-okay-regex-match.exp
new file mode 100644
index 000000000000..950103539123
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-regex-match.exp
@@ -0,0 +1 @@
+[ true true false true true true true false false true false [ "foobar" ] [ "FOO" ] [ "/path/to/" "/path/to" "foobar" "nix" ] [ null null "foobar" "cc" ] ]
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-regex-match.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-regex-match.nix
new file mode 100644
index 000000000000..f774e00a215a
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-regex-match.nix
@@ -0,0 +1,29 @@
+with builtins;
+
+let
+
+  matches = pat: s: match pat s != null;
+
+  splitFN = match "((.*)/)?([^/]*)\\.(nix|cc)";
+
+in
+
+[
+  (matches "foobar" "foobar")
+  (matches "fo*" "f")
+  (matches "fo+" "f")
+  (matches "fo*" "fo")
+  (matches "fo*" "foo")
+  (matches "fo+" "foo")
+  (matches "fo{1,2}" "foo")
+  (matches "fo{1,2}" "fooo")
+  (matches "fo*" "foobar")
+  (matches "[[:space:]]+([^[:space:]]+)[[:space:]]+" "  foo   ")
+  (matches "[[:space:]]+([[:upper:]]+)[[:space:]]+" "  foo   ")
+
+  (match "(.*)\\.nix" "foobar.nix")
+  (match "[[:space:]]+([[:upper:]]+)[[:space:]]+" "  FOO   ")
+
+  (splitFN "/path/to/foobar.nix")
+  (splitFN "foobar.cc")
+]