tess/
prompt.rs

1//! Status-line prompt customization. Wraps the existing `DisplayTemplate`
2//! parser from `format.rs`, validating against a fixed set of prompt-only
3//! placeholder names. Rendered against a `PromptContext` populated by the
4//! viewport on every frame.
5//!
6//! Escape sequences supported in template literals (inherited from
7//! `DisplayTemplate`): `\<` (literal `<`), `\\` (literal `\`), `\n` / `\t`
8//! / `\r` (newline / tab / CR), `\e` / `\x1b` / `\033` (ESC — useful for
9//! embedding raw SGR sequences in prompts).
10
11use crate::format::DisplayTemplate;
12
13/// All placeholders that resolve in a prompt template. Validation against
14/// this list happens at parse time; unknown placeholders produce a clear
15/// startup error.
16const PROMPT_FIELDS: &[&str] = &[
17    "label",
18    "top",
19    "bottom",
20    "total",
21    "pct",
22    "rec-top",
23    "rec-bottom",
24    "rec-total",
25    "rec-block",
26    "wrap-offset",
27    "format-tag",
28    "filter-tag",
29    "grep-tag",
30    "or-tag",
31    "hide-tag",
32    "search-tag",
33    "pretty-tag",
34    "live-tag",
35    "follow-tag",
36    "preprocess-failed-tag",
37    "file-index-tag",
38    "tag-tag",
39];
40
41#[derive(Debug, Clone)]
42pub struct ParsedPrompt {
43    template: DisplayTemplate,
44}
45
46impl ParsedPrompt {
47    /// Parse a prompt template. Validates that all `<field>` placeholders
48    /// are known prompt fields. Returns the parse error on failure.
49    pub fn parse(source: &str) -> Result<Self, String> {
50        let field_names: Vec<String> =
51            PROMPT_FIELDS.iter().map(|s| s.to_string()).collect();
52        let template = DisplayTemplate::compile(source, &field_names)?;
53        Ok(Self { template })
54    }
55
56    /// Render the prompt against a context. Missing fields render as empty.
57    pub fn render(&self, ctx: &PromptContext) -> String {
58        self.template.render(|name| ctx.lookup(name))
59    }
60
61    pub fn source(&self) -> &str {
62        self.template.source()
63    }
64}
65
66/// All data the prompt template can resolve. Populated by the viewport
67/// once per frame and passed to `ParsedPrompt::render`.
68#[derive(Debug, Default)]
69pub struct PromptContext {
70    pub label: String,
71    pub top: usize,
72    pub bottom: usize,
73    pub total: usize,
74    pub pct: u8,
75    pub rec_top: usize,
76    pub rec_bottom: usize,
77    pub rec_total: usize,
78    pub records_mode: bool,
79    pub wrap_offset: String,
80    pub format_tag: String,
81    pub filter_tag: String,
82    pub grep_tag: String,
83    pub or_tag: String,
84    pub hide_tag: String,
85    pub search_tag: String,
86    pub pretty_tag: String,
87    pub live_tag: String,
88    pub follow_tag: String,
89    pub preprocess_failed_tag: String,
90    pub file_index_tag: String,
91    pub tag_tag: String,
92}
93
94impl PromptContext {
95    fn lookup(&self, name: &str) -> Option<String> {
96        match name {
97            "label" => Some(self.label.clone()),
98            "top" => Some(self.top.to_string()),
99            "bottom" => Some(self.bottom.to_string()),
100            "total" => Some(self.total.to_string()),
101            "pct" => Some(self.pct.to_string()),
102            "rec-top" => Some(self.rec_top.to_string()),
103            "rec-bottom" => Some(self.rec_bottom.to_string()),
104            "rec-total" => Some(self.rec_total.to_string()),
105            "rec-block" => Some(if self.records_mode {
106                format!(
107                    "L{}-{}/{}  R{}-{}/{}",
108                    self.top, self.bottom, self.total,
109                    self.rec_top, self.rec_bottom, self.rec_total,
110                )
111            } else {
112                format!("{}-{}/{}", self.top, self.bottom, self.total)
113            }),
114            "wrap-offset" => Some(self.wrap_offset.clone()),
115            "format-tag" => Some(self.format_tag.clone()),
116            "filter-tag" => Some(self.filter_tag.clone()),
117            "grep-tag" => Some(self.grep_tag.clone()),
118            "or-tag" => Some(self.or_tag.clone()),
119            "hide-tag" => Some(self.hide_tag.clone()),
120            "search-tag" => Some(self.search_tag.clone()),
121            "pretty-tag" => Some(self.pretty_tag.clone()),
122            "live-tag" => Some(self.live_tag.clone()),
123            "follow-tag" => Some(self.follow_tag.clone()),
124            "preprocess-failed-tag" => Some(self.preprocess_failed_tag.clone()),
125            "file-index-tag" => Some(self.file_index_tag.clone()),
126            "tag-tag" => Some(self.tag_tag.clone()),
127            _ => None,
128        }
129    }
130}
131
132#[cfg(test)]
133mod tests {
134    use super::*;
135
136    #[test]
137    fn parse_literal_only_template() {
138        let p = ParsedPrompt::parse("hello").unwrap();
139        let ctx = PromptContext::default();
140        assert_eq!(p.render(&ctx), "hello");
141    }
142
143    #[test]
144    fn parse_field_template() {
145        let p = ParsedPrompt::parse("<label> <pct>%").unwrap();
146        let ctx = PromptContext {
147            label: "file.log".into(),
148            pct: 42,
149            ..Default::default()
150        };
151        assert_eq!(p.render(&ctx), "file.log 42%");
152    }
153
154    #[test]
155    fn parse_rejects_unknown_field() {
156        let err = ParsedPrompt::parse("<bogus>").unwrap_err();
157        assert!(err.contains("bogus"), "error mentions field name: {err}");
158    }
159
160    #[test]
161    fn parse_handles_escaped_left_angle() {
162        // `\<` is the escape for a literal `<`; `>` outside a field is always literal.
163        let p = ParsedPrompt::parse(r"\<not a field>").unwrap();
164        let ctx = PromptContext::default();
165        assert_eq!(p.render(&ctx), "<not a field>");
166    }
167
168    #[test]
169    fn parse_handles_escaped_backslash() {
170        let p = ParsedPrompt::parse(r"a\\b").unwrap();
171        let ctx = PromptContext::default();
172        assert_eq!(p.render(&ctx), "a\\b");
173    }
174
175    #[test]
176    fn render_resolves_empty_tags_to_nothing() {
177        let p = ParsedPrompt::parse("<label><filter-tag><grep-tag>").unwrap();
178        let ctx = PromptContext { label: "x".into(), ..Default::default() };
179        assert_eq!(p.render(&ctx), "x");
180    }
181
182    #[test]
183    fn or_tag_renders() {
184        let p = ParsedPrompt::parse("<grep-tag><or-tag>").unwrap();
185        let ctx = PromptContext { grep_tag: "  [grep]".into(), or_tag: "  [or]".into(), ..Default::default() };
186        assert_eq!(p.render(&ctx), "  [grep]  [or]");
187    }
188
189    #[test]
190    fn render_resolves_populated_tags() {
191        let p = ParsedPrompt::parse("<grep-tag><hide-tag>").unwrap();
192        let ctx = PromptContext {
193            grep_tag: "  [grep]".into(),
194            hide_tag: "  [hide]".into(),
195            ..Default::default()
196        };
197        assert_eq!(p.render(&ctx), "  [grep]  [hide]");
198    }
199
200    #[test]
201    fn rec_block_renders_records_mode_form() {
202        let p = ParsedPrompt::parse("<rec-block>").unwrap();
203        let ctx = PromptContext {
204            top: 1, bottom: 3, total: 3,
205            rec_top: 1, rec_bottom: 2, rec_total: 2,
206            records_mode: true,
207            ..Default::default()
208        };
209        assert_eq!(p.render(&ctx), "L1-3/3  R1-2/2");
210    }
211
212    #[test]
213    fn rec_block_renders_line_mode_form() {
214        let p = ParsedPrompt::parse("<rec-block>").unwrap();
215        let ctx = PromptContext {
216            top: 1, bottom: 3, total: 3,
217            records_mode: false,
218            ..Default::default()
219        };
220        assert_eq!(p.render(&ctx), "1-3/3");
221    }
222
223    #[test]
224    fn render_preprocess_failed_tag_resolves_when_populated() {
225        let p = ParsedPrompt::parse("<preprocess-failed-tag>").unwrap();
226        let ctx = PromptContext {
227            preprocess_failed_tag: "  [preprocess-failed: bad cmd]".into(),
228            ..Default::default()
229        };
230        assert_eq!(p.render(&ctx), "  [preprocess-failed: bad cmd]");
231    }
232
233    #[test]
234    fn render_file_index_tag_resolves_when_populated() {
235        let p = ParsedPrompt::parse("<file-index-tag>").unwrap();
236        let ctx = PromptContext {
237            file_index_tag: "  [2/3]".into(),
238            ..Default::default()
239        };
240        assert_eq!(p.render(&ctx), "  [2/3]");
241    }
242
243    #[test]
244    fn render_file_index_tag_empty_when_unset() {
245        let p = ParsedPrompt::parse("<file-index-tag>").unwrap();
246        let ctx = PromptContext::default();
247        assert_eq!(p.render(&ctx), "");
248    }
249
250    #[test]
251    fn render_tag_tag_resolves_when_populated() {
252        let p = ParsedPrompt::parse("<tag-tag>").unwrap();
253        let ctx = PromptContext {
254            tag_tag: "  [tag: foo (2/3)]".into(),
255            ..Default::default()
256        };
257        assert_eq!(p.render(&ctx), "  [tag: foo (2/3)]");
258    }
259
260    #[test]
261    fn render_tag_tag_empty_when_unset() {
262        let p = ParsedPrompt::parse("<tag-tag>").unwrap();
263        let ctx = PromptContext::default();
264        assert_eq!(p.render(&ctx), "");
265    }
266}
tess/prompt.rs

tess/
prompt.rs
