changed a lot of stuff

src/ui.rs

@@ -0,0 +1,72 @@
+use crate::parse::{ClassFile, ParseErr};
+use std::error::Error;
+use std::io::Write;
+
+pub fn display_class<W: Write>(mut w: W, class: &ClassFile) -> Result<(), Box<dyn Error>> {
+    let cp = &class.constant_pool;
+
+    writeln!(
+        w,
+        ".class ({:#X?}) file version {}.{}",
+        class.magic, class.major_version, class.minor_version
+    )?;
+
+    writeln!(w)?;
+
+    writeln!(
+        w,
+        "class {} extends {}{} {{",
+        &class.this_class.get(cp)?.name_index.get(cp)?,
+        if class.interfaces.len() == 0 {
+            "".to_string()
+        } else {
+            format!(
+                " implements {}",
+                // this is absolutely terrible but it works i guess
+                class
+                    .interfaces
+                    .iter()
+                    .map(|i| i.get(cp))
+                    .collect::<Result<Vec<_>, ParseErr>>()?
+                    .iter()
+                    .map(|i| i.name_index.get(cp))
+                    .collect::<Result<Vec<_>, ParseErr>>()?
+                    .join(",")
+            )
+        },
+        match class.super_class.get(cp)? {
+            None => "<none>",
+            Some(class) => &class.name_index.get(cp)?,
+        }
+    )?;
+
+    writeln!(w, " Class Attributes:")?;
+    for attr in &class.attributes {
+        writeln!(w, "  {}", &attr.attribute_name_index.get(cp)?)?;
+    }
+    writeln!(w)?;
+
+    writeln!(w, " Class Fields:")?;
+    for field in &class.fields {
+        writeln!(
+            w,
+            "  {} {}",
+            &field.descriptor_index.get(cp)?,
+            &field.name_index.get(cp)?
+        )?;
+    }
+    writeln!(w)?;
+
+    writeln!(w, " Class Methods:")?;
+    for method in &class.methods {
+        writeln!(
+            w,
+            "  {} {}",
+            &method.descriptor_index.get(cp)?,
+            &method.name_index.get(cp)?,
+        )?;
+    }
+
+    writeln!(w, "}}")?;
+    Ok(())
+}