Add Decimal number type.

Cargo.toml

@@ -37,6 +37,7 @@ no_float = []       # no floating-point
 f32_float = []      # set FLOAT=f32
 only_i32 = []       # set INT=i32 (useful for 32-bit systems)
 only_i64 = []       # set INT=i64 (default) and disable support for all other integer types
+decimal = [ "rust_decimal" ] # add the Decimal number type
 no_index = []       # no arrays and indexing
 no_object = []      # no custom objects
 no_function = [ "no_closure" ]  # no script-defined functions (meaning no closures)
@@ -44,7 +45,7 @@ no_closure = []     # no automatic sharing and capture of anonymous functions to
 no_module = []      # no modules
 internals = []      # expose internal data structures
 unicode-xid-ident = ["unicode-xid"] # allow Unicode Standard Annex #31 for identifiers.
-metadata = [ "serde", "serde_json"] # enables exporting functions metadata to JSON
+metadata = [ "serde", "serde_json" ] # enables exporting functions metadata to JSON
 
 # compiling for no-std
 no_std = [ "smallvec/union", "num-traits/libm", "hashbrown", "core-error", "libm", "ahash/compile-time-rng" ]
@@ -98,6 +99,11 @@ version = "0.2"
 default_features = false
 optional = true
 
+[dependencies.rust_decimal]
+version = "1.10"
+default_features = false
+optional = true
+
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 instant= { version = "0.1" } # WASM implementation of std::time::Instant