Add latte::vector to generate arbitrary vectors

Easy generation of lists, sets and maps with an arbitrary item generator function.

(cherry picked from commit b29b0b6)

Cargo.toml

@@ -35,7 +35,7 @@ num_cpus = "1.13.0"
 openssl = "0.10.38"
 parse_duration = "2.1.1"
 pin-project = "1.1"
-plotters = { version = "0.3", default-features = false, features = ["line_series", "svg_backend", "full_palette"]}
+plotters = { version = "0.3", default-features = false, features = ["line_series", "svg_backend", "full_palette"] }
 rand = { version = "0.8", default-features = false, features = ["small_rng", "std"] }
 rand_distr = "0.4"
 regex = "1.5"
@@ -54,7 +54,7 @@ tokio = { version = "1", features = ["rt", "rt-multi-thread", "time", "parking_l
 tokio-stream = "0.1"
 tracing = "0.1"
 tracing-appender = "0.2"
-tracing-subscriber = {  version = "0.3", features = ["env-filter"] }
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 try-lock = "0.2.3"
 uuid = { version = "1.1", features = ["v4"] }
 walkdir = "2"

src/scripting/functions.rs

@@ -9,7 +9,7 @@ use rand::prelude::StdRng;
 use rand::{Rng, SeedableRng};
 use rune::macros::{quote, MacroContext, TokenStream};
 use rune::parse::Parser;
-use rune::runtime::{Mut, Ref, VmError, VmResult};
+use rune::runtime::{Function, Mut, Ref, VmError, VmResult};
 use rune::{ast, vm_try, Value};
 use statrs::distribution::{Normal, Uniform};
 use std::collections::HashMap;
@@ -71,6 +71,10 @@ pub fn hash(i: i64) -> i64 {
 /// Computes hash of two integer values.
 #[rune::function]
 pub fn hash2(a: i64, b: i64) -> i64 {
+    hash2_inner(a, b)
+}
+
+fn hash2_inner(a: i64, b: i64) -> i64 {
     let mut hash = MetroHash64::new();
     a.hash(&mut hash);
     b.hash(&mut hash);
@@ -127,6 +131,16 @@ pub fn text(seed: i64, len: usize) -> String {
         .collect()
 }
 
+#[rune::function]
+pub fn vector(len: usize, generator: Function) -> VmResult<Vec<Value>> {
+    let mut result = Vec::with_capacity(len);
+    for i in 0..len {
+        let value = vm_try!(generator.call((i,)));
+        result.push(value);
+    }
+    VmResult::Ok(result)
+}
+
 /// Generates 'now' timestamp
 #[rune::function]
 pub fn now_timestamp() -> i64 {

src/scripting/mod.rs

@@ -46,6 +46,7 @@ fn try_install(
 
     latte_module.function_meta(functions::blob)?;
     latte_module.function_meta(functions::text)?;
+    latte_module.function_meta(functions::vector)?;
     latte_module.function_meta(functions::now_timestamp)?;
     latte_module.function_meta(functions::hash)?;
     latte_module.function_meta(functions::hash2)?;