2 files changed, 39 insertions, 15 deletions
diff --git a/src/parse.rs b/src/parse/mod.rs
index 61d268d..4f38f9b 100644
--- a/src/parse.rs
+++ b/src/parse/mod.rs
@@ -1,16 +1,19 @@
 use crate::BString;
 
-pub trait Stage {
-    type Str: std::fmt::Debug + Clone;
+#[cfg(test)]
+mod test;
+
+pub trait Stage : PartialEq {
+    type Str: std::fmt::Debug + Clone + PartialEq;
 }
 
 pub trait CmdDisplay {
     fn cdisplay(&self, w: &mut dyn std::io::Write) -> std::io::Result<()>;
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct PreExpansion;
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct PostExpansion;
 
 impl Stage for PreExpansion {
@@ -29,7 +32,7 @@ pub trait Expander {
     fn expand_cmd(&mut self, c: Ast<PostExpansion>) -> Res<BString, Self::Error>;
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub enum Ast<T: Stage> {
     FunDecl(FunDecl<T>),
     VarAssign(VarAssign<T>),
@@ -121,12 +124,17 @@ impl CmdDisplay for ExpString {
         if self.parts.len() == 1 && self.parts[0].is_boring() {
             write!(
                 w,
-                "estr({})",
+                "estr(b\"{}\")",
                 self.parts[0].clone().unwrap_boring().escape_ascii()
             )
         } else {
             write!(w, "str([")?;
+            let mut first = true;
             for part in self.parts.iter() {
+                if !first {
+                    write!(w, ",")?;
+                }
+                first = false;
                 part.cdisplay(w)?;
             }
             write!(w, "])")
@@ -138,7 +146,7 @@ impl CmdDisplay for StringPart {
     fn cdisplay(&self, w: &mut dyn std::io::Write) -> std::io::Result<()> {
         match self {
             StringPart::Boring(items) => {
-                write!(w, "bstr(")?;
+                write!(w, "plain(")?;
                 items.as_slice().cdisplay(w)?;
                 write!(w, ")")
             }
@@ -186,7 +194,7 @@ impl Ast<PreExpansion> {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct FunBody {
     pub body: Box<Ast<PreExpansion>>,
 }
@@ -219,7 +227,7 @@ impl Parse for FunBody {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct FunDecl<S: Stage> {
     pub name: S::Str,
     pub body: FunBody,
@@ -247,7 +255,7 @@ impl FunDecl<PreExpansion> {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct VarAssign<S: Stage> {
     pub var: S::Str,
     pub val: S::Str,
@@ -285,7 +293,7 @@ impl VarAssign<PreExpansion> {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct Pipes<T: Stage> {
     pub cmds: Vec<Command<T>>,
 }
@@ -300,7 +308,7 @@ impl Pipes<PreExpansion> {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub enum StringPart {
     Boring(BString),
     Var(VarName),
@@ -319,7 +327,7 @@ impl StringPart {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 /// `"hi ${var} $(cmd) "` gets mapped to `[Boring("hi "), Var("var"), String(" "), Cmd(...), Boring(" ")]`
 pub struct ExpString {
     parts: Vec<StringPart>,
@@ -357,7 +365,7 @@ fn is_var_name(x: u8) -> bool {
     x.is_ascii_alphanumeric() || x == b'_'
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct VarName {
     name: BString,
 }
@@ -509,7 +517,7 @@ impl Parse for ExpString {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct Command<T: Stage> {
     pub cmd: T::Str,
     pub args: Vec<T::Str>,
diff --git a/src/parse/test.rs b/src/parse/test.rs
new file mode 100644
index 0000000..6cd7793
--- /dev/null
+++ b/src/parse/test.rs
@@ -0,0 +1,16 @@
+use super::*;
+
+fn parse(x: &[u8]) -> Ast<PreExpansion> {
+    do_parse(x).unwrap()
+}
+
+#[test]
+fn command_interp() {
+    assert_eq!(
+        parse(br#"echo "$(echo hi)""#),
+        pipes([cmd([
+            estr(b"echo"),
+            str([cmdp(pipes([cmd([estr(b"echo"), estr(b"hi")]),])),])
+        ]),])
+    );
+}