added basic method to check syntax command input

src/syntax/check.rs

@@ -4,10 +4,8 @@ use super::{
 };
 
 pub fn check(
-    syntax: Vec<PipelineElement>,
-    raw_source: &str,
-    file_id: FileId,
-) -> Result<Vec<PipelineElement>, Vec<SyntaxError>> {
+    syntax: &Vec<PipelineElement>,
+) -> Result<(), Vec<SyntaxError>> {
     let mut errs = Vec::new();
 
     if let Err(e_span) = check_missing_streamer(&syntax) {
@@ -23,7 +21,7 @@ pub fn check(
     }
 
     if errs.is_empty() {
-        Ok(syntax)
+        Ok(())
     } else {
         Err(errs)
     }