convert more stdlib functions and add rounding

converted with_base and with_math

mers_lib/examples/02_own_variable.rs

@@ -1,61 +0,0 @@
-use std::sync::Arc;
-
-use mers_lib::{
-    data::{self, Data, Type},
-    errors::CheckError,
-    prelude_compile::{parse, Config, Source},
-    program::parsed::CompInfo,
-};
-
-fn main() {
-    eprintln!("This is valid:");
-    run("my_custom_var.debug.rust_func.debug".to_owned()).unwrap();
-    eprintln!();
-
-    eprintln!("This is not:");
-    let e = run("5.rust_func".to_owned()).err().unwrap();
-    eprintln!("{e:?}");
-}
-fn run(src: String) -> Result<(), CheckError> {
-    let mut source = Source::new_from_string(src);
-    let srca = Arc::new(source.clone());
-    let parsed = parse(&mut source, &srca)?;
-
-    // Add our custom variables to the `Config`
-    let (mut i1, mut i2, mut i3) = Config::new()
-        .bundle_std()
-        .add_var(
-            "my_custom_var".to_owned(),
-            Data::new(data::string::String(format!("my custom value!"))),
-        )
-        .add_var(
-            "rust_func".to_owned(),
-            Data::new(data::function::Function::new_generic(
-                |arg| {
-                    // If the input is a string, the output is a string.
-                    // Otherwise, the function is used incorrectly.
-                    if arg.is_included_in_single(&data::string::StringT) {
-                        Ok(Type::new(data::string::StringT))
-                    } else {
-                        // Wrong argument type. The code won't compile and this is the error message shown to the user.
-                        Err(format!("Can't call rust_func with non-string argument {arg}!").into())
-                    }
-                },
-                |arg| {
-                    let arg = arg.get();
-                    let arg = &arg
-                        .as_any()
-                        .downcast_ref::<data::string::String>()
-                        .unwrap()
-                        .0;
-                    Ok(Data::new(data::string::String(arg.chars().rev().collect())))
-                },
-            )),
-        )
-        .infos();
-
-    let compiled = parsed.compile(&mut i1, CompInfo::default())?;
-    compiled.check(&mut i3, None)?;
-    compiled.run(&mut i2)?;
-    Ok(())
-}