diff --git a/README.md b/README.md
index 74808dd..64a331c 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@ Kalk is a calculator (both program and library) that supports user-defined varia
 * Syntax highlighting
 * Special-symbol completion on tab. Eg. write `sqrt` and press tab. It will be turned into `√`.
 * Sum function: `sum(start, to, expression)` Eg. `sum(1, 3, 2n+1)` is the same as `2*1+1 + 2*2+1 + 2*3+1` = `15`
+* Load a file including predefined functions and constants. For example, if you're going to use Kalk for physics, you load up your file with physics functions/constants when starting Kalk. `-i file`
 
 ## Installing
 Make sure you have `diffutils` `gcc` `make` and `m4` installed.
diff --git a/kalk/README.md b/kalk/README.md
index 3878294..a238b55 100644
--- a/kalk/README.md
+++ b/kalk/README.md
@@ -18,12 +18,11 @@ f(a, 2)
 * Special-symbol completion on tab. Eg. write `sqrt` and press tab. It will be turned into `√`.
 
 ## Usage
-```
+```rust
 use kalk::parser;
-
-...
-let parser_context = parser::Context::new();
-assert_eq!(parser_context.eval("5*3").unwrap().unwrap(), 15);
+let mut parser_context = parser::Context::new();
+let precision = 53;
+assert_eq!(parser::eval(&mut parser_context, "5*3", precision).unwrap().unwrap(), 15);
 ```
 
 ## Compiling