Flesh out syntax part of documentation

Signed-off-by: Marcel Müller <neikos@neikos.email>

src/lib.rs

@@ -27,6 +27,75 @@
     cfg_attr(doc, doc = ::document_features::document_features!())
 )]
 //!
+//! ## Syntax
+//!
+//! Nomo tries to keep a consistent syntax across its features.
+//! The main concepts are:
+//!
+//! [`nomo`](crate) uses `{{ }}` as its identifiers. Each of them forms a 'block'.
+//!
+//! There are two kinds of blocks:
+//!
+//! - `{{= <expr> }}` Interpolations
+//! - `{{ <control> }}` everything else
+//!
+//! ### Expressions
+//!
+//! An expression in [`nomo`](crate) is anything that produces a value. Notably, control structures
+//! _do not_ create values. This is different to rust.
+//!
+//! So for example this does not work:
+//!
+//! ```nomo
+//! {{= if is_active "Active" else "Inactive" end }}
+//! ```
+//!
+//! If you wish to conditionally output something, you would write:
+//!
+//! ```nomo
+//! {{ if is_active }}
+//!     Active
+//! {{ else }}
+//!     Inactive
+//! {{ end }}
+//! ```
+//!
+//! In expressions you can write:
+//! - Mathematical expressions (`+-*/`)
+//! - Logical/Binary expressions (`&&`, `||`, `>`, ...)
+//! - Literals (`12`, `292.21`, `"Hello"`)
+//!
+//! ### Interpolations
+//!
+//! Interpolations is how one prints out data. A [`NomoValue`] can be printed if it is a:
+//!
+//! - String
+//! - Integer/SignedInteger
+//! - Bool
+//! - Float
+//!
+//! All other values will result in an error.
+//!
+//! ### Control Structures
+//!
+//! [`Nomo`](crate) supports several control structures:
+//!
+//! **Conditions `if/else`**:
+//!
+//! ```nomo
+//! {{ if <expr> }}
+//! {{ else if <expr> }}
+//! {{ else }}
+//! {{ end }}
+//! ```
+//!
+//! **Loops `for .. in`**
+//!
+//! ```nomo
+//! {{ for <identifier> in <expr> }}
+//! {{ else }}
+//! {{ end }}
+//! ```
 
 use std::collections::HashMap;
 

src/value.rs

@@ -246,12 +246,12 @@ impl NomoValue {
     pub(crate) fn try_to_string(&self) -> Option<String> {
         match self {
             NomoValue::String { value } => Some(value.to_string()),
-            NomoValue::Array { .. } => None,
             NomoValue::Bool { value } => Some(value.to_string()),
-            NomoValue::Object { .. } => None,
             NomoValue::Integer { value } => Some(value.to_string()),
             NomoValue::SignedInteger { value } => Some(value.to_string()),
             NomoValue::Float { value } => Some(value.to_string()),
+            NomoValue::Array { .. } => None,
+            NomoValue::Object { .. } => None,
             NomoValue::Iterator { .. } => None,
             NomoValue::Undefined => None,
         }