pipe parsing

1 files changed, 58 insertions, 6 deletions

diff --git a/src/parse.rs b/src/parse.rs
index cc495b1..fae00a3 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -18,14 +18,20 @@ pub struct Command {
 }
 
 enum ParseError {
+    /// "clean" EOF, i.e. not in the middle of something
+    Eof,
+
+    /// "unclean" EOF, i.e. EOF after beginning a quoted string
     Incomplete,
+
     UnexpectedPipe,
+
     UnknownChar(char),
 }
 
 type Result<T> = std::result::Result<T, ParseError>;
 
-pub fn parse(x: &str) -> Result<Ast> {
+pub fn do_parse(x: &str) -> Result<Ast> {
     let chars: Vec<char> = x.chars().collect();
     Ast::parse(&mut &chars[..])
 }
@@ -34,12 +40,22 @@ trait Parse: Sized {
     fn parse(b: &mut &[char]) -> Result<Self>;
 }
 
+#[inline(always)]
+fn parse<T: Parse>(b: &mut &[char]) -> Result<T> {
+    T::parse(b)
+}
+
 fn spaces(b: &mut &[char]) {
     while let Some(' ' | '\t') = b.get(0) {
         *b = &b[1..];
     }
 }
 
+#[inline(always)]
+fn adv(b: &mut &[char]) {
+    *b = &b[1..]
+}
+
 fn parse_quoted_string(b: &mut &[char], delim: char) -> Result<String> {
     // TODO: escape sequence stuff
 
@@ -47,12 +63,12 @@ fn parse_quoted_string(b: &mut &[char], delim: char) -> Result<String> {
     let mut s = String::new();
     while b.len() > 0 {
         if b[0] == delim {
-            *b = &b[1..];
+            adv(b);
             return Ok(s);
         }
 
         s.push(b[0]);
-        *b = &b[1..];
+        adv(b);
     }
     Err(ParseError::Incomplete)
 }
@@ -61,13 +77,13 @@ impl Parse for String {
     fn parse(b: &mut &[char]) -> Result<Self> {
         spaces(b);
         if b.is_empty() {
-            return Err(ParseError::Incomplete);
+            return Err(ParseError::Eof);
         }
         let c = b[0];
         if c == '|' {
             Err(ParseError::UnexpectedPipe)
         } else if c == '\'' || c == '"' {
-            *b = &b[1..];
+            adv(b);
             parse_quoted_string(b, c)
         } else if c.is_ascii_graphic() {
             parse_quoted_string(b, ' ')
@@ -79,6 +95,42 @@ impl Parse for String {
 
 impl Parse for Ast {
     fn parse(b: &mut &[char]) -> Result<Self> {
-        todo!()
+        Ok(Self::Pipes(parse(b)?))
+    }
+}
+
+impl Parse for Command {
+    fn parse(b: &mut &[char]) -> Result<Self> {
+        let path: String = parse(b)?;
+        let mut args = Vec::new();
+        loop {
+            let arg: Result<String> = parse(b);
+            match arg {
+                Ok(arg) => args.push(arg),
+                Err(ParseError::Eof | ParseError::UnexpectedPipe) => break,
+                Err(e) => Err(e)?,
+            }
+        }
+        Ok(Self { path, args })
+    }
+}
+
+impl Parse for Pipes {
+    fn parse(b: &mut &[char]) -> Result<Self> {
+        let cmds: Vec<Command> = vec![parse(b)?];
+
+        loop {
+            spaces(b);
+            if b.is_empty() {
+                return Ok(Pipes { cmds });
+            }
+
+            let c = b[0];
+            if c == '|' {
+                adv(b);
+            } else {
+                Err(ParseError::UnknownChar(c))?;
+            }
+        }
     }
 }