init

.gitignore

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+/target

Cargo.toml

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+[package]
+name = "simple-replace-templete-engine"
+version = "0.1.0"
+authors = ["wucong <1875486458@qq.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+regex = "1.3.4"
+failure = "0.1.6"

src/lib.rs

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+/// return the variable which inside input
+/// # Remarks
+/// str which format like {prefix}{var}{prefix} will be identified as variable
+///!```
+/// use simple_replace_templete_engine::get_variables;
+/// let vars = get_variables("hello _t_name_t_","_t_");
+/// assert_eq!(vars,vec!["name".to_owned()]);
+///!```
+pub fn get_variables(input: &str, prefix: &str) -> Vec<String> {
+    use regex::Regex;
+    use std::collections::HashSet;
+    let regex = Regex::new(&format!(r#"(?m){}[^\s]*{}"#, prefix, prefix)).unwrap();
+    let result = regex.find_iter(input);
+    let mut vars = HashSet::new();
+    for mat in result {
+        let var = mat
+            .as_str()
+            .trim_start_matches(prefix)
+            .trim_end_matches(prefix)
+            .to_string();
+        vars.insert(var);
+    }
+    return vars.into_iter().collect();
+}
+
+/// render templete with give map
+///!```
+/// use std::collections::HashMap;
+/// use simple_replace_templete_engine::render;
+/// 
+/// let map = {
+///     let mut map = HashMap::new();
+///     map.insert("name".to_owned(), "me".to_owned());
+///     map
+/// };
+/// let templete_str = "hello _t_name_t_".to_owned();
+///
+/// let ret = render(&templete_str, "_t_", &map).unwrap();
+/// assert_eq!(ret,"hello me".to_owned());
+///!```
+pub fn render(
+    input: &str,
+    prefix: &str,
+    map: &std::collections::HashMap<String, String>,
+) -> Result<String, failure::Error> {
+    use regex::Regex;
+    let need_names = get_variables(input, prefix);
+    for n in need_names.iter() {
+        if map.get(n).is_none() {
+            return Err(failure::format_err!("could not get variable {}", n));
+        }
+    }
+
+    let mut input = input.to_string();
+    for n in need_names.iter() {
+        let regex = Regex::new(&format!(r#"(?m){}[^\s]*{}"#, prefix, prefix)).unwrap();
+        let replace_str = map.get(n).unwrap();
+        input = regex.replace_all(&input, replace_str.as_str()).to_string();
+    }
+    return Ok(input);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_get_variable() {
+        let vars = get_variables("hello _t_name_t_", "_t_");
+        assert_eq!(vars, vec!["name".to_owned()]);
+    }
+    #[test]
+    fn test_replace() {
+        use std::collections::HashMap;
+        const PREFIX: &'static str = "_t_";
+        let mut map = HashMap::new();
+        map.insert("name".to_owned(), "me".to_owned());
+        let templete_str = "hello _t_name_t_".to_owned();
+
+        let ret = render(&templete_str, PREFIX, &map).unwrap();
+        assert_eq!(ret, "hello me".to_owned());
+    }
+}