write read_colors and get_color_num functions

Author: viz

.gitignore

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+/target
+**/*.rs.bk

Cargo.lock

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+[package]
+name = "tm"
+version = "0.1.0"
+authors = ["viz <[email protected]>"]
+edition = "2018"
+
+[dependencies]

Cargo.toml

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+fn main() {
+    println!("Hello, world!");
+}

src/main.rs

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+use std::fs;
+use std::process;
+
+fn read_colors(path: &str) -> Vec<String> {
+    /*
+     * read colors from a raw text file located at path
+     * append the colors to a vector of String and return it
+     */
+    let mut colors: Vec<String> = Vec::new();
+
+    let contents = fs::read_to_string(&path)
+        .unwrap_or_else(|err| {
+            println!("error: {}", err);
+            process::exit(0);
+    });
+
+    let contents: Vec<&str> = contents.lines().collect();
+
+    for color in contents {
+        colors.push(String::from(color));
+    }
+
+    return colors;
+}
+
+fn get_color_num(line: &String) -> Vec<String> {
+    /*
+     * in a template file, Xn indicates the nth color
+     * which should be substituted. this function retuns
+     * all the n in a line
+     */
+
+    // the vector which will be returned
+    let mut result: Vec<String> = Vec::new();
+
+    let matches: Vec<_> = line.match_indices(char::is_numeric).collect();
+
+    // find a better to avoid edge cases
+    let mut prev_index = 1000;
+
+    for m in matches.iter() {
+        // get the index number
+        let ind = m.0;
+
+        // get the matching character
+        let mut ch = String::from(m.1);
+
+        // get the previous char is an X
+        let prev_ch = line.get(ind-1..ind).unwrap_or("");
+
+        // check if the previous char is an X
+        // if it is not, skip the iteration
+        if prev_ch != "X" {
+            continue;
+        }
+
+        // get the next char and see if it is numeric
+        let next_ch = line.get(ind+1..ind+2).unwrap_or("");
+        let next_ch: Vec<_> = next_ch.matches(char::is_numeric).collect();
+
+        // if it is numeric, then set the approriate prev_index and skip
+        // the iteration
+        if next_ch.len() > 0 {
+            prev_index = ind;
+            continue;
+        }
+
+        // check if the previous index is the one we stored
+        // if it is, then it means we have to prepend it
+        if ind-1 == prev_index {
+            ch = String::from(format!("{}{}", line.get(prev_index..ind).unwrap(), ch));
+        }
+
+        // update the prev_index
+        prev_index = ind;
+
+        result.push(String::from(ch));
+    }
+
+    return result
+}