Move tag.rs module, add basic --json

The `--json` flag is currently only respected by `mensa meals`.
Relates to #4.

src/config/args.rs

@@ -7,7 +7,7 @@ use std::path::PathBuf;
 
 use crate::{
     error::{Error, Result},
-    meal::tag::Tag,
+    tag::Tag,
 };
 
 use super::PriceTags;
@@ -40,6 +40,10 @@ pub struct Args {
                 )]
     pub color: ColorWhen,
 
+    /// Print plain json. Useful for shell scripts.
+    #[structopt(long, global = true, takes_value = false)]
+    pub json: bool,
+
     #[structopt(subcommand)]
     pub command: Option<Command>,
 }
@@ -92,7 +96,11 @@ pub struct MealsCommand {
     pub canteen_id: Option<usize>,
 
     /// Specify which price tags should be displayed
-    #[structopt(long, short, env = "MENSA_PRICES", possible_values = &PriceTags::variants())]
+    #[structopt(long,
+                short,
+                env = "MENSA_PRICES",
+                possible_values = &PriceTags::variants(),
+                case_insensitive = true)]
     pub price: Option<Vec<PriceTags>>,
 
     #[structopt(long, env = "MENSA_OVERWRITE_FILTER", takes_value = false)]

src/config/rule.rs

@@ -4,7 +4,8 @@ use std::convert::TryFrom;
 
 use crate::{
     error::{Error, Result},
-    meal::{tag::Tag, Meal},
+    meal::Meal,
+    tag::Tag,
 };
 
 #[derive(Debug, Clone, Default, Deserialize)]

src/main.rs

@@ -109,15 +109,18 @@ mod config;
 mod error;
 mod geoip;
 mod meal;
+mod tag;
 
-use config::{
-    args::{parse_human_date, Args, MealsCommand},
+use crate::{
+    canteen::Canteen,
+    config::{
+        args::{parse_human_date, Args, Command, MealsCommand},
         State,
+    },
+    error::{Error, Result, ResultExt},
+    meal::Meal,
+    tag::Tag,
 };
-use error::{Error, Result, ResultExt};
-use meal::{tag::Tag, Meal};
-
-use crate::{canteen::Canteen, config::args::Command};
 
 const ENDPOINT: &str = "https://openmensa.org/api/v2";
 const MIN_TERM_WIDTH: usize = 20;
@@ -152,7 +155,7 @@ fn real_main() -> Result<()> {
         Some(Command::Meals(cmd)) => {
             let state = State::from(state, cmd);
             let meals = Meal::fetch(&state)?;
-            Meal::print_all(&state, &meals);
+            Meal::print_all(&state, &meals)?;
         }
         Some(Command::Tomorrow(cmd)) => {
             // Works like the meals command. But we replace the date with tomorrow!
@@ -160,7 +163,7 @@ fn real_main() -> Result<()> {
             cmd.date = parse_human_date("tomorrow").unwrap();
             let state = State::from(state, &cmd);
             let meals = Meal::fetch(&state)?;
-            Meal::print_all(&state, &meals);
+            Meal::print_all(&state, &meals)?;
         }
         Some(Command::Canteens(cmd)) => {
             let state = State::from(state, cmd);
@@ -172,7 +175,7 @@ fn real_main() -> Result<()> {
             let cmd = MealsCommand::default();
             let state = State::from(state, &cmd);
             let meals = Meal::fetch(&state)?;
-            Meal::print_all(&state, &meals);
+            Meal::print_all(&state, &meals)?;
         }
     }
     Ok(())

src/meal/mod.rs

@@ -2,8 +2,7 @@ use chrono::Duration;
 use core::fmt;
 use itertools::Itertools;
 use lazy_static::lazy_static;
-use owo_colors::{OwoColorize, Stream};
-use serde::Deserialize;
+use serde::{Deserialize, Serialize};
 use unicode_width::UnicodeWidthStr;
 
 use std::collections::HashSet;
@@ -11,14 +10,12 @@ use std::collections::HashSet;
 use crate::{
     cache::fetch_json,
     config::{args::MealsCommand, MealsState, PriceTags},
-    error::{pass_info, Result},
-    get_sane_terminal_dimensions, State, ENDPOINT,
+    error::{pass_info, Error, Result},
+    get_sane_terminal_dimensions,
+    tag::Tag,
+    State, ENDPOINT,
 };
 
-pub mod tag;
-
-use self::tag::Tag;
-
 const NAME_PRE: &str = " ╭───╴";
 const NAME_PRE_PLAIN: &str = " - ";
 const NAME_CONTINUE_PRE: &str = " ┊    ";
@@ -36,9 +33,10 @@ lazy_static! {
     static ref TTL_MEALS: Duration = Duration::hours(1);
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Debug, Serialize, Deserialize)]
 #[serde(from = "RawMeal")]
 pub struct Meal {
+    #[serde(rename = "id")]
     pub _id: usize,
     pub name: String,
     pub tags: HashSet<Tag>,
@@ -57,7 +55,7 @@ struct RawMeal {
     category: String,
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Debug, Serialize, Deserialize)]
 #[cfg_attr(debug, serde(deny_unknown_fields))]
 pub struct Prices {
     students: f32,
@@ -123,17 +121,24 @@ impl Meal {
     /// Print the given meals.
     ///
     /// Thi will respect passed cli arguments and the configuration.
-    pub fn print_all(state: &MealsState, meals: &[Self]) {
+    pub fn print_all(state: &MealsState, meals: &[Self]) -> Result<()> {
         // Load the filter which is used to select which meals to print.
         let filter = state.get_filter();
         // Load the favourites which will be used for marking meals.
         let favs = state.get_favs_rule();
+        let meals = meals.iter().filter(|meal| filter.is_match(meal));
+        if state.args.json {
+            let stdout = std::io::stdout();
+            let output = stdout.lock();
+            serde_json::to_writer_pretty(output, &meals.collect::<Vec<_>>())
+                .map_err(|why| Error::Serializing(why, "writing meals as json"))
+        } else {
             for meal in meals {
-            if filter.is_match(meal) {
                 let is_fav = favs.is_match(meal);
                 println!();
                 meal.print(state, is_fav);
             }
+            Ok(())
         }
     }
 

src/tag.rs

@@ -1,7 +1,7 @@
 use lazy_static::lazy_static;
 use num_enum::{IntoPrimitive, TryFromPrimitive};
 use regex::RegexSet;
-use serde::Deserialize;
+use serde::{Deserialize, Serialize};
 use strum::{Display, EnumIter};
 
 use crate::config::State;
@@ -38,6 +38,9 @@ lazy_static! {
     .unwrap();
 }
 
+/// A tag describing a meal.
+///
+/// Contains allergy information, descriptions and categories.
 #[derive(
     Debug,
     Clone,
@@ -49,6 +52,7 @@ lazy_static! {
     PartialOrd,
     IntoPrimitive,
     TryFromPrimitive,
+    Serialize,
     Deserialize,
     EnumIter,
     Display,
@@ -84,6 +88,7 @@ pub enum Tag {
 }
 
 impl Tag {
+    /// Try deriving [`Tag`]s from the `raw` tag.
     pub fn parse_str(raw: &str) -> Vec<Self> {
         TAG_RE
             .matches(raw)
@@ -92,6 +97,9 @@ impl Tag {
             .collect()
     }
 
+    /// Is this a primary tag?
+    ///
+    /// Primary tags have an associated emoji and are not allergy information.
     pub fn is_primary(&self) -> bool {
         use Tag::*;
         match self {
@@ -102,10 +110,15 @@ impl Tag {
         }
     }
 
+    /// Is this **not** a primary tag?
     pub fn is_secondary(&self) -> bool {
         !self.is_primary()
     }
 
+    /// Describe this [`Tag`] with english words.
+    ///
+    /// This should add information where the enum variant itself
+    /// does not suffice.
     pub fn describe(&self) -> &'static str {
         match self {
             Self::Alcohol => "Contains alcohol",
@@ -140,7 +153,8 @@ impl Tag {
 
     /// This formats an identifier for this tag.
     ///
-    /// Will respect any settings given.
+    /// Will respect any settings given, i.e. emojis will be used
+    /// unless the output should be plain.
     pub fn as_id<Cmd>(&self, state: &State<Cmd>) -> String {
         match self {
             Self::Vegan => if_plain!(state: "🌱".into(), "Vegan".into()),