feat: add json_output

src/commonmark.rs

@@ -16,21 +16,19 @@
 //! This module implements CommonMark output for a struct
 //! representing a single entry in the manual.
 
-use std::collections::HashMap;
-
-use std::io::{Result, Write};
+use serde::Serialize;
 
 /// Represent a single function argument name and its (optional)
 /// doc-string.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Serialize)]
 pub struct SingleArg {
     pub name: String,
     pub doc: Option<String>,
 }
 
 /// Represent a function argument, which is either a flat identifier
 /// or a pattern set.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Serialize)]
 pub enum Argument {
     /// Flat function argument (e.g. `n: n * 2`).
     Flat(SingleArg),
@@ -99,16 +97,42 @@ fn handle_indentation(raw: &str) -> String {
     }
 }
 
+/// Generate the identifier for CommonMark.
+/// ident is used as URL Encoded link to the function and has thus stricter rules (i.e. "' " in "lib.map' "  is not allowed).
+pub(crate) fn get_identifier(prefix: &String, category: &String, name: &String) -> String {
+    let name_prime = name.replace('\'', "-prime");
+    vec![prefix, category, &name_prime]
+        .into_iter()
+        .filter(|x| !x.is_empty())
+        .cloned()
+        .collect::<Vec<String>>()
+        .join(".")
+}
+
+/// Generate the title for CommonMark.
+/// the title is the human-readable name of the function.
+pub(crate) fn get_title(prefix: &String, category: &String, name: &String) -> String {
+    vec![prefix, category, name]
+        .into_iter()
+        .filter(|x| !x.is_empty())
+        .cloned()
+        .collect::<Vec<String>>()
+        .join(".")
+}
+
 /// Represents a single manual section describing a library function.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Serialize)]
 pub struct ManualEntry {
     /// Prefix for the category (e.g. 'lib' or 'utils').
     pub prefix: String,
 
-    /// Name of the function category (e.g. 'strings', 'trivial', 'attrsets')
+    /// Name of the function category (e.g. 'strings', 'trivial', 'attrsets').
     pub category: String,
 
-    /// Name of the section (used as the title)
+    /// Location of the function.
+    pub location: Option<String>,
+
+    /// Name of the section (used as the title).
     pub name: String,
 
     /// Type signature (if provided). This is not actually a checked
@@ -122,61 +146,44 @@ pub struct ManualEntry {
     /// Usage example for the entry.
     pub example: Option<String>,
 
-    /// Arguments of the function
+    /// Arguments of the function.
     pub args: Vec<Argument>,
 }
 
 impl ManualEntry {
-    /// Generate the identifier and title for CommonMark.
-    /// title is the human-readable name of the function.
-    /// ident is used as URL Encoded link to the function and has thus stricter rules (i.e. "' " in "lib.map' "  is not allowed).
     pub(crate) fn get_ident_title(&self) -> (String, String) {
-        let name_prime = self.name.replace('\'', "-prime");
-
-        let ident = vec![&self.prefix, &self.category, &name_prime]
-            .into_iter()
-            .filter(|x| !x.is_empty())
-            .cloned()
-            .collect::<Vec<String>>()
-            .join(".");
-
-        let title = vec![&self.prefix, &self.category, &self.name]
-            .into_iter()
-            .filter(|x| !x.is_empty())
-            .cloned()
-            .collect::<Vec<String>>()
-            .join(".");
-
+        let ident = get_identifier(&self.prefix, &self.category, &self.name);
+        let title = get_title(&self.prefix, &self.category, &self.name);
         (ident, title)
     }
+
     /// Write a single CommonMark entry for a documented Nix function.
-    pub fn write_section<W: Write>(
-        self,
-        locs: &HashMap<String, String>,
-        writer: &mut W,
-    ) -> Result<()> {
+    pub fn write_section(self, output: &mut String) -> String {
         let (ident, title) = self.get_ident_title();
-        writeln!(writer, "## `{}` {{#function-library-{}}}\n", title, ident)?;
+        output.push_str(&format!(
+            "## `{}` {{#function-library-{}}}\n\n",
+            title, ident
+        ));
 
         // <subtitle> (type signature)
         if let Some(t) = &self.fn_type {
             if t.lines().count() > 1 {
-                writeln!(writer, "**Type**:\n```\n{}\n```\n", t)?;
+                output.push_str(&format!("**Type**:\n```\n{}\n```\n\n", t));
             } else {
-                writeln!(writer, "**Type**: `{}`\n", t)?;
+                output.push_str(&format!("**Type**: `{}`\n\n", t));
             }
         }
 
         // Primary doc string
         // TODO: Split paragraphs?
         for paragraph in &self.description {
-            writeln!(writer, "{}\n", paragraph)?;
+            output.push_str(&format!("{}\n\n", paragraph));
         }
 
         // Function argument names
         if !self.args.is_empty() {
             for arg in self.args {
-                writeln!(writer, "{}", arg.format_argument())?;
+                output.push_str(&format!("{}\n", arg.format_argument()));
             }
         }
 
@@ -185,19 +192,18 @@ impl ManualEntry {
         // TODO: In grhmc's version there are multiple (named)
         // examples, how can this be achieved automatically?
         if let Some(example) = &self.example {
-            writeln!(
-                writer,
-                "::: {{.example #function-library-example-{}}}",
+            output.push_str(&format!(
+                "::: {{.example #function-library-example-{}}}\n",
                 ident
-            )?;
-            writeln!(writer, "# `{}` usage example\n", title)?;
-            writeln!(writer, "```nix\n{}\n```\n:::\n", example.trim())?;
+            ));
+            output.push_str(&format!("# `{}` usage example\n\n", title));
+            output.push_str(&format!("```nix\n{}\n```\n:::\n\n", example.trim()));
         }
 
-        if let Some(loc) = locs.get(&ident) {
-            writeln!(writer, "Located at {loc}.\n")?;
+        if let Some(loc) = self.location {
+            output.push_str(&String::from(format!("Located at {loc}.\n\n")));
         }
 
-        Ok(())
+        output.to_string()
     }
 }

src/legacy.rs

@@ -3,11 +3,12 @@ use rnix::{
     SyntaxKind, SyntaxNode,
 };
 use rowan::ast::AstNode;
+use std::collections::HashMap;
 
 use crate::{
     commonmark::{Argument, ManualEntry, SingleArg},
     format::handle_indentation,
-    retrieve_doc_comment, DocComment,
+    get_identifier, retrieve_doc_comment, DocComment,
 };
 
 #[derive(Debug)]
@@ -18,10 +19,22 @@ pub struct LegacyDocItem {
 }
 
 impl LegacyDocItem {
-    pub fn into_entry(self, prefix: &str, category: &str) -> ManualEntry {
+    pub fn into_entry(
+        self,
+        prefix: &str,
+        category: &str,
+        locs: &HashMap<String, String>,
+    ) -> ManualEntry {
+        let ident = get_identifier(
+            &prefix.to_string(),
+            &category.to_string(),
+            &self.name.to_string(),
+        );
+
         ManualEntry {
             prefix: prefix.to_string(),
             category: category.to_string(),
+            location: locs.get(&ident).cloned(),
             name: self.name,
             description: self
                 .comment

src/main.rs

@@ -41,9 +41,8 @@ use rnix::{
 use rowan::{ast::AstNode, WalkEvent};
 use std::fs;
 
+use serde::Serialize;
 use std::collections::HashMap;
-use std::io;
-use std::io::Write;
 
 use clap::Parser;
 use std::path::PathBuf;
@@ -56,6 +55,10 @@ struct Options {
     #[arg(short, long, default_value_t = String::from("lib"))]
     prefix: String,
 
+    /// Whether to output JSON.
+    #[arg(short, long, default_value_t = false)]
+    json_output: bool,
+
     /// Name of the function category (e.g. 'strings', 'attrsets').
     #[arg(short, long)]
     category: String,
@@ -93,6 +96,12 @@ struct DocItem {
     comment: DocComment,
 }
 
+#[derive(Debug, Serialize)]
+struct JsonFormat {
+    version: u32,
+    entries: Vec<ManualEntry>,
+}
+
 enum DocItemOrLegacy {
     LegacyDocItem(LegacyDocItem),
     DocItem(DocItem),
@@ -222,6 +231,7 @@ fn collect_bindings(
     node: &SyntaxNode,
     prefix: &str,
     category: &str,
+    locs: &HashMap<String, String>,
     scope: HashMap<String, ManualEntry>,
 ) -> Vec<ManualEntry> {
     for ev in node.preorder() {
@@ -232,7 +242,7 @@ fn collect_bindings(
                     if let Some(apv) = AttrpathValue::cast(child.clone()) {
                         entries.extend(
                             collect_entry_information(apv)
-                                .map(|di| di.into_entry(prefix, category)),
+                                .map(|di| di.into_entry(prefix, category, locs)),
                         );
                     } else if let Some(inh) = Inherit::cast(child) {
                         // `inherit (x) ...` needs much more handling than we can
@@ -259,7 +269,12 @@ fn collect_bindings(
 
 // Main entrypoint for collection
 // TODO: document
-fn collect_entries(root: rnix::Root, prefix: &str, category: &str) -> Vec<ManualEntry> {
+fn collect_entries(
+    root: rnix::Root,
+    prefix: &str,
+    category: &str,
+    locs: &HashMap<String, String>,
+) -> Vec<ManualEntry> {
     // we will look into the top-level let and its body for function docs.
     // we only need a single level of scope for this.
     // since only the body can export a function we don't need to implement
@@ -276,15 +291,16 @@ fn collect_entries(root: rnix::Root, prefix: &str, category: &str) -> Vec<Manual
                     LetIn::cast(n.clone()).unwrap().body().unwrap().syntax(),
                     prefix,
                     category,
+                    locs,
                     n.children()
                         .filter_map(AttrpathValue::cast)
                         .filter_map(collect_entry_information)
-                        .map(|di| (di.name.to_string(), di.into_entry(prefix, category)))
+                        .map(|di| (di.name.to_string(), di.into_entry(prefix, category, locs)))
                         .collect(),
                 );
             }
             WalkEvent::Enter(n) if n.kind() == SyntaxKind::NODE_ATTR_SET => {
-                return collect_bindings(&n, prefix, category, Default::default());
+                return collect_bindings(&n, prefix, category, locs, Default::default());
             }
             _ => (),
         }
@@ -307,9 +323,7 @@ fn retrieve_description(nix: &rnix::Root, description: &str, category: &str) ->
     )
 }
 
-fn main() {
-    let mut output = io::stdout();
-    let opts = Options::parse();
+fn main_with_options(opts: Options) -> String {
     let src = fs::read_to_string(&opts.file).unwrap();
     let locs = match opts.locs {
         None => Default::default(),
@@ -321,12 +335,30 @@ fn main() {
     let nix = rnix::Root::parse(&src).ok().expect("failed to parse input");
     let description = retrieve_description(&nix, &opts.description, &opts.category);
 
-    // TODO: move this to commonmark.rs
-    writeln!(output, "{}", description).expect("Failed to write header");
-
-    for entry in collect_entries(nix, &opts.prefix, &opts.category) {
-        entry
-            .write_section(&locs, &mut output)
-            .expect("Failed to write section")
+    let entries = collect_entries(nix, &opts.prefix, &opts.category, &locs);
+
+    if opts.json_output {
+        let json_string = match serde_json::to_string(&JsonFormat {
+            version: 1,
+            entries,
+        }) {
+            Ok(json) => json,
+            Err(error) => panic!("Problem converting entries to JSON: {error:?}"),
+        };
+        json_string
+    } else {
+        // TODO: move this to commonmark.rs
+        let mut output = description + "\n";
+
+        for entry in entries {
+            entry.write_section(&mut output);
+        }
+        output
     }
 }
+
+fn main() {
+    let opts = Options::parse();
+    let output = main_with_options(opts);
+    println!("{}", output)
+}

src/snapshots/nixdoc__test__main.snap

@@ -1,8 +1,10 @@
 ---
-source: src/main.rs
+source: src/test.rs
+assertion_line: 23
 expression: output
 ---
 # string manipulation functions {#sec-functions-library-strings}
+String manipulation functions.
 
 ## `lib.strings.concatStrings` {#function-library-lib.strings.concatStrings}
 
@@ -1693,5 +1695,3 @@ levenshteinAtMost 3 "This is a sentence" "this is a sentense."
 :::
 
 Located at [lib/strings.nix:1183](https://github.com/NixOS/nixpkgs/blob/580dd2124db98c13c3798af23c2ecf6277ec7d9e/lib/strings.nix#L1183) in `<nixpkgs>`.
-
-