Make toml an optional feature

Cargo.toml

@@ -26,7 +26,6 @@ enum-map = "0.6.0"
 enumset = "0.4.0"
 log = "0.4.8"
 owning_ref = "0.4.0"
-toml = "0.5.1"
 unicode-segmentation = "1.3.0"
 unicode-width = "0.1.5"
 xi-unicode = "0.2.0"
@@ -38,6 +37,10 @@ chrono = "0.4.7"
 cfg-if = "0.1.9"
 ahash = "0.2.12"
 
+[dependencies.toml]
+optional = true
+version = "0.5.1"
+
 [dependencies.num]
 default-features = false
 version = "0.2.0"

examples/theme.rs

@@ -3,6 +3,9 @@ use cursive::Cursive;
 
 fn main() {
     let mut siv = Cursive::default();
+
+    #[cfg(feature = "toml")]
+    {
         // You can load a theme from a file at runtime for fast development.
         siv.load_theme_file("assets/style.toml").unwrap();
 
@@ -17,6 +20,19 @@ fn main() {
             .title("Themed dialog")
             .button("Quit", |s| s.quit()),
         );
+    }
+
+    #[cfg(not(feature = "toml"))]
+    {
+        siv.add_layer(
+            Dialog::around(TextView::new(
+                "Run this example again with the `toml` feature!\n\n\
+                 cargo run --example theme --features toml",
+            ))
+            .title("Themed dialog - missing `toml` feature")
+            .button("Quit", |s| s.quit()),
+        );
+    }
 
     siv.run();
 }

src/cursive.rs

@@ -1,5 +1,6 @@
 use std::any::Any;
 use std::num::NonZeroU32;
+#[cfg(feature = "toml")]
 use std::path::Path;
 use std::time::Duration;
 
@@ -405,9 +406,12 @@ impl Cursive {
             .clear(self.theme.palette[theme::PaletteColor::Background]);
     }
 
+    #[cfg(feature = "toml")]
     /// Loads a theme from the given file.
     ///
     /// `filename` must point to a valid toml file.
+    ///
+    /// Must have the `toml` feature enabled.
     pub fn load_theme_file<P: AsRef<Path>>(
         &mut self,
         filename: P,
@@ -415,9 +419,12 @@ impl Cursive {
         theme::load_theme_file(filename).map(|theme| self.set_theme(theme))
     }
 
+    #[cfg(feature = "toml")]
     /// Loads a theme from the given string content.
     ///
     /// Content must be valid toml.
+    ///
+    /// Must have the `toml` feature enabled.
     pub fn load_toml(&mut self, content: &str) -> Result<(), theme::Error> {
         theme::load_toml(content).map(|theme| self.set_theme(theme))
     }

src/theme/mod.rs

@@ -171,11 +171,13 @@ pub use self::color_style::{ColorStyle, ColorType};
 pub use self::effect::Effect;
 pub use self::palette::{Palette, PaletteColor};
 pub use self::style::Style;
+#[cfg(feature = "toml")]
 use std::fs::File;
 use std::io;
+#[cfg(feature = "toml")]
 use std::io::Read;
+#[cfg(feature = "toml")]
 use std::path::Path;
-use toml;
 
 /// Represents the style a Cursive application will use.
 #[derive(Clone, Debug)]
@@ -199,6 +201,7 @@ impl Default for Theme {
 }
 
 impl Theme {
+    #[cfg(feature = "toml")]
     fn load_toml(&mut self, table: &toml::value::Table) {
         if let Some(&toml::Value::Boolean(shadow)) = table.get("shadow") {
             self.shadow = shadow;
@@ -219,23 +222,30 @@ impl Theme {
 pub enum Error {
     /// An error occured when reading the file.
     Io(io::Error),
+
+    #[cfg(feature = "toml")]
     /// An error occured when parsing the toml content.
     Parse(toml::de::Error),
 }
 
+#[cfg(feature = "toml")]
 impl From<io::Error> for Error {
     fn from(err: io::Error) -> Self {
         Error::Io(err)
     }
 }
 
+#[cfg(feature = "toml")]
 impl From<toml::de::Error> for Error {
     fn from(err: toml::de::Error) -> Self {
         Error::Parse(err)
     }
 }
 
+#[cfg(feature = "toml")]
 /// Loads a theme from file and sets it as active.
+///
+/// Must have the `toml` feature enabled.
 pub fn load_theme_file<P: AsRef<Path>>(filename: P) -> Result<Theme, Error> {
     let content = {
         let mut content = String::new();
@@ -248,6 +258,9 @@ pub fn load_theme_file<P: AsRef<Path>>(filename: P) -> Result<Theme, Error> {
 }
 
 /// Loads a theme string and sets it as active.
+///
+/// Must have the `toml` feature enabled.
+#[cfg(feature = "toml")]
 pub fn load_toml(content: &str) -> Result<Theme, Error> {
     let table = toml::de::from_str(content)?;
 

src/theme/palette.rs

@@ -1,7 +1,7 @@
 use super::Color;
 use enum_map::{enum_map, Enum, EnumMap};
+#[cfg(feature = "toml")]
 use log::warn;
-use toml;
 
 use std::ops::{Index, IndexMut};
 
@@ -173,6 +173,7 @@ impl Default for Palette {
 }
 
 // Iterate over a toml
+#[cfg(feature = "toml")]
 fn iterate_toml<'a>(
     table: &'a toml::value::Table,
 ) -> impl Iterator<Item = (&'a str, PaletteNode)> + 'a {
@@ -216,6 +217,7 @@ fn iterate_toml<'a>(
 }
 
 /// Fills `palette` with the colors from the given `table`.
+#[cfg(feature = "toml")]
 pub(crate) fn load_toml(palette: &mut Palette, table: &toml::value::Table) {
     // TODO: use serde for that?
     // Problem: toml-rs doesn't do well with Enums...