improve parsing (very janky)

src/misc.rs

@@ -1,7 +1,62 @@
 use wasm_bindgen::prelude::*;
+use meval::Expr;
 
 pub type DrawResult<T> = Result<T, Box<dyn std::error::Error>>;
 
+pub fn test_func_basic(function_string: String) -> String {
+    let expr_result = function_string.parse();
+    let expr_error = match &expr_result {
+        Ok(_) => "".to_string(),
+        Err(error) => format!("{}", error),
+    };
+    if !expr_error.is_empty() {
+        return expr_error;
+    }
+
+    let expr: Expr = expr_result.unwrap();
+    let func_result = expr.bind("x");
+    let func_error = match &func_result {
+        Ok(_) => "".to_string(),
+        Err(error) => format!("{}", error),
+    };
+    if !func_error.is_empty() {
+        return func_error;
+    }
+
+    "".to_string()
+}
+
+
+// EXTREMELY Janky function that tries to put asterisks in the proper places to be parsed
+pub fn add_asterisks(function: String) -> String {
+    let letters: Vec<char>= "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".chars().collect();
+    let numbers: Vec<char> = "0123456789".chars().collect();
+    let function_chars = function.chars();
+    let mut output_string: String = String::new();
+    let mut prev_char: char = ' ';
+    for c in function_chars {
+        if prev_char == ')' {
+            if c == '(' {
+                output_string += "*";
+            } else if (c == 'x') | numbers.contains(&c) {
+                output_string += "*"
+            }
+        } else if letters.contains(&c) {
+            if numbers.contains(&prev_char) {
+                output_string += "*";
+            }
+        } else if numbers.contains(&c) {
+            if letters.contains(&prev_char) {
+                output_string += "*";
+            }
+        }
+        prev_char = c;
+        output_string += &c.to_string();
+    }
+
+    return output_string;
+}
+
 /// Result of screen to chart coordinates conversion.
 #[wasm_bindgen]
 pub struct Point {