4 files changed, 158 insertions, 141 deletions

diff --git a/src/error.rs b/src/error.rs
new file mode 100644
index 0000000..a2b6d96
--- /dev/null
+++ b/src/error.rs
@@ -0,0 +1,45 @@
+
+use core::error::Error;
+use std::fmt;
+
+use crate::position::*;
+
+#[derive(Debug)]
+pub struct CrimError {
+    position: Position,
+    what: String,
+}
+
+impl CrimError {
+    pub fn new( position: Position, what: String ) -> Self {
+        CrimError {
+            position,
+            what,
+        }
+    }
+
+    pub fn eos( context: &str ) -> Self {
+        CrimError {
+            position: Position::none(),
+            what: format!("Premature end of stream while looking for {}", context),
+        }
+    }
+
+    pub fn what(&self) -> &str {
+        &self.what
+    }
+
+    pub fn start(&self) -> &Position {
+        &self.position
+    }
+}
+
+impl fmt::Display for CrimError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "Error parsing input: {}", "yeah")
+    }
+}
+
+impl Error for CrimError { }
+
+pub type CrimResult<T> = Result<T, CrimError>;
diff --git a/src/lexer.rs b/src/lexer.rs
index 7228866..2fa29ce 100644
--- a/src/lexer.rs
+++ b/src/lexer.rs
@@ -22,6 +22,9 @@ pub enum SymbolType<'a> {
     Loop,
     Equals,
     Period,
+    If,
+    ElseIf,
+    Else,
     Token(&'a str),
     Literal(&'a str),
     Text(&'a str),
@@ -246,6 +249,9 @@ impl<'a> Lexer<'a> {
                 "show" => SymbolType::Show,
                 "output" => SymbolType::Output,
                 "loop" => SymbolType::Loop,
+                "if" => SymbolType::If,
+                "elseif" => SymbolType::ElseIf,
+                "else" => SymbolType::Else,
                 _ => SymbolType::Token(s)
             }, start_pos, end_pos ))
         }
diff --git a/src/lib.rs b/src/lib.rs
index feb00f0..9b838f3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,8 +6,9 @@ use std::time::SystemTime;
 mod lexer;
 mod parser;
 mod position;
+mod error;
 
-pub use parser::ParseError;
+pub use error::{CrimError,CrimResult};
 pub use position::*;
 
 #[derive(Debug)]
@@ -38,7 +39,7 @@ struct View {
 }
 
 impl View {
-    fn process(&self, input: &impl MappedStructure) -> Result<Context, ParseError> {
+    fn process(&self, input: &impl MappedStructure) -> Result<Context, CrimError> {
         let mut out_vars = Context::new();
         for output in &self.outputs {
             let mut buf = String::new();
@@ -61,6 +62,9 @@ type Properties = HashMap<String, String>;
 enum Token {
     Loop(Identifier, Vec<Token>),
     Show(Identifier,Properties),
+    If(Identifier, Vec<Token>),
+    ElseIf(Identifier, Vec<Token>),
+    Else(Vec<Token>),
     Text(String),
 }
 
@@ -165,13 +169,13 @@ impl Crimtag {
         Ok(())
     }
 
-    pub fn load_static(&mut self, data: &str) -> Result<(),ParseError> {
+    pub fn load_static(&mut self, data: &str) -> Result<(),CrimError> {
         let source_id = self.id_source( &ViewSource::Static );
         let p = parser::Parser::new();
         self.register_views( p.parse( &data, source_id )? )
     }
 
-    pub fn load_external(&mut self, key: &str, data: &str) -> Result<(),ParseError> {
+    pub fn load_external(&mut self, key: &str, data: &str) -> Result<(),CrimError> {
         let source_id = self.id_source(
             &ViewSource::External{ key: key.to_string()}
             );
@@ -182,7 +186,7 @@ impl Crimtag {
             )
     }
 
-    fn register_views(&mut self, views: Vec<View>) -> Result<(),ParseError> {
+    fn register_views(&mut self, views: Vec<View>) -> Result<(),CrimError> {
         for view in views {
             self.views.insert( view.name.clone(), view );
         }
@@ -201,15 +205,15 @@ impl Crimtag {
         }
     }
 
-    pub fn render_partial(&self, view: &str, input: &impl MappedStructure ) -> Result<Context,ParseError> {
+    pub fn render_partial(&self, view: &str, input: &impl MappedStructure ) -> Result<Context,CrimError> {
         if let Some(view) = self.views.get(view) {
             return view.process( input )
         } else {
-            return Err(ParseError::new(Position::new(0,0),"No such view found"));
+            return Err(CrimError::new(Position::none(),"No such view found".into()));
         }
     }
 
-    pub fn render(&self, view: &str, input: &impl MappedStructure ) -> Result<String,ParseError> {
+    pub fn render(&self, view: &str, input: &impl MappedStructure ) -> Result<String,CrimError> {
         if let Some(view) = self.views.get( view ) {
             let mut output = view.process( input )?;
             if let Some(l) = &view.layout {
@@ -220,17 +224,17 @@ impl Crimtag {
 
                     Ok(s)
                 } else {
-                    Err(ParseError::new(Position::new(0,0),"No content found in root layout."))
+                    Err(CrimError::new(Position::none(), "No content found in root layout.".into()))
                 }
             }
 
         } else {
-            Err(ParseError::new(Position::new(0,0),"No such view found"))
+            Err(CrimError::new(Position::none(),"No such view found".into()))
         }
     }
 }
 
-fn exec(input: &impl MappedStructure, tokens: &Vec<Token>, buf: &mut String) -> Result<(),ParseError> {
+fn exec(input: &impl MappedStructure, tokens: &Vec<Token>, buf: &mut String) -> Result<(),CrimError> {
     for token in tokens {
         match token {
             Token::Loop(ident,code) => {
@@ -279,6 +283,7 @@ fn exec(input: &impl MappedStructure, tokens: &Vec<Token>, buf: &mut String) ->
             Token::Text(s) => {
                 buf.push_str( s );
             }
+            _ => {}
         }
     }
     Ok(())
diff --git a/src/parser.rs b/src/parser.rs
index 07bbd93..83144fb 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -1,41 +1,6 @@
 use crate::lexer::*;
 use crate::*;
 
-use core::error::Error;
-use std::fmt;
-
-#[derive(Debug)]
-pub struct ParseError {
-    position: Position,
-    what: String,
-}
-
-impl ParseError {
-    pub fn new( position: Position, what: &str ) -> Self {
-        ParseError {
-            position,
-            what: what.to_string(),
-        }
-    }
-
-    pub fn eos( context: &str ) -> Self {
-        ParseError {
-            position: Position::none(),
-            what: format!("Premature end of stream while looking for {}", context),
-        }
-    }
-}
-
-impl fmt::Display for ParseError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "Error parsing input: {}", "yeah")
-    }
-}
-
-impl Error for ParseError { }
-
-pub type ParseResult<T> = Result<T, ParseError>;
-
 struct Context<'a> {
     cur: [Option<Symbol<'a>>;2],
     icur: usize,
@@ -70,9 +35,9 @@ impl<'a> Context<'a> {
         self.cur[(self.icur+1)%2]
     }
 
-    pub fn check_unwrapped<T: Fn( &SymbolType, &SymbolType ) -> bool>(&self, context: &str, f: T) -> ParseResult<bool> {
+    pub fn check_unwrapped<T: Fn( &SymbolType, &SymbolType ) -> bool>(&self, context: &str, f: T) -> CrimResult<bool> {
         if self.cur().is_none() || self.peek().is_none() {
-            Err(ParseError::eos( context ))
+            Err(CrimError::eos( context ))
         } else  {
             Ok(f( self.cur().unwrap().symbol(), self.peek().unwrap().symbol()))
         }
@@ -84,34 +49,37 @@ impl<'a> Context<'a> {
 }
 
 trait SymbolHelper {
-    fn is<T: Fn( &SymbolType ) -> bool>(&self, context: &str, f: T ) -> ParseResult<bool>;
-    fn is_valid_tag_name(&self) -> ParseResult<bool>;
+    fn is<T: Fn( &SymbolType ) -> bool>(&self, context: &str, f: T ) -> CrimResult<bool>;
+    fn is_valid_tag_name(&self) -> CrimResult<bool>;
 }
 
 impl<'a> SymbolHelper for Option<Symbol<'a>> {
-    fn is<T: Fn( &SymbolType ) -> bool>(&self, context: &str, f: T ) -> ParseResult<bool> {
+    fn is<T: Fn( &SymbolType ) -> bool>(&self, context: &str, f: T ) -> CrimResult<bool> {
         if let Some(st) = self {
             Ok(f( &st.symbol() ))
         } else {
-            Err(ParseError::eos( context ))
+            Err(CrimError::eos( context ))
         }
     }
     
-    fn is_valid_tag_name(&self) -> ParseResult<bool> {
+    fn is_valid_tag_name(&self) -> CrimResult<bool> {
         if let Some(st) = self {
             Ok(match st.symbol() {
                 SymbolType::Token(_) |
                 SymbolType::View |
                 SymbolType::Output |
                 SymbolType::Loop |
+                SymbolType::If |
+                SymbolType::ElseIf |
+                SymbolType::Else |
                 SymbolType::Show => true,
                 _ => false
             })
         } else {
-            Err(ParseError{
-                position: Position::new(0,0),
-                what: "Unexpeceted end of stream.".to_string()
-            })
+            Err(CrimError::new(
+                Position::none(),
+                "Unexpeceted end of stream.".to_string()
+                ))
         }
     }
 }
@@ -202,21 +170,17 @@ impl Parser {
         }
     }
 
-    fn lex_error<T>(&self, error: &Symbol) -> ParseResult<T> {
+    fn lex_error<T>(&self, error: &Symbol) -> CrimResult<T> {
         if let SymbolType::Error{what} = error.symbol() {
-            Err(ParseError {
-                position: error.start().clone(),
-                what: format!("What: {:?}", *what)
-            })
+            Err(CrimError::new( *error.start(),
+                format!("What: {:?}", *what)
+            ))
         } else {
-            Err(ParseError {
-                position: Position::new(0,0),
-                what: "Not an error?".to_string(),
-            })
+            Err(CrimError::new( Position::none(), "Not an error?".into()))
         }
     }
 
-    pub fn parse(&self, src: &str, source: usize ) -> ParseResult<Vec<View>> {
+    pub fn parse(&self, src: &str, source: usize ) -> CrimResult<Vec<View>> {
         let ll = Lexer::new( src );
         let mut ctx = Context::new( ll, source );
 
@@ -224,7 +188,7 @@ impl Parser {
         self.p_input( &mut ctx )
     }
 
-    fn p_input(&self, ctx: &mut Context ) -> ParseResult<Vec<View>> {
+    fn p_input(&self, ctx: &mut Context ) -> CrimResult<Vec<View>> {
         let mut children = Vec::new();
         loop {
             if ctx.cur().is_none() {
@@ -247,13 +211,12 @@ impl Parser {
         Ok(children)
     }
 
-    fn parse_tag_view(&self, ctx: &mut Context) -> ParseResult<View> {
+    fn parse_tag_view(&self, ctx: &mut Context) -> CrimResult<View> {
         let tb = self.parse_open_tag( ctx )?;
         if !tb.is_name( &SymbolType::View ) {
-            return Err(ParseError{
-                position: tb.start_pos(),
-                what: "Unexpected tag type, only frament allowed at root".to_string(),
-            });
+            return Err(CrimError::new(tb.start_pos(),
+                "Unexpected tag type, only frament allowed at root".into()
+            ));
         }
 
         if tb.is_unary() {
@@ -265,7 +228,7 @@ impl Parser {
         //println!("--parse-tag-view-- tag parsed, next token: {:?}", ctx.cur() );
         loop {
             if ctx.cur().is_none() {
-                return Err(ParseError::eos(format!("close tag for {:?}", tb.name()).as_str()))
+                return Err(CrimError::eos(format!("close tag for {:?}", tb.name()).as_str()))
             }
             match ctx.cur().unwrap().symbol() {
                 SymbolType::Text(s) => {
@@ -297,52 +260,56 @@ impl Parser {
                             });
                         } else {
                             if !all_text {
-                                return Err(ParseError{
-                                    position: *end.start(),
-                                    what: "You cannot mix non-output and output tags in a view.".to_string()
-                                });
+                                return Err(CrimError::new(
+                                    *end.start(),
+                                    "You cannot mix non-output and output tags in a view.".to_string()
+                                ));
                             }
                         }
                         return tb.build_view(ctx,outputs);
                     } else {
                         // They don't match, complain.
-                        return Err(ParseError{
-                            position: *end.start(),
-                            what: "Mismatched open and closing tags.".to_string()
-                        });
+                        return Err(CrimError::new(
+                            *end.start(),
+                            "Mismatched open and closing tags.".to_string()
+                        ));
                     }
                 }
                 SymbolType::Error{..} => {
                     return self.lex_error( &ctx.cur().unwrap() );
                 }
                 _ => {
-                    return Err(ParseError{
-                        position: *ctx.cur().unwrap().start(),
-                        what: format!("Unexpected tag in view root: {:?}", ctx.cur().unwrap().symbol())
-                    });
+                    return Err(CrimError::new(
+                        *ctx.cur().unwrap().start(),
+                        format!("Unexpected tag in view root: {:?}", ctx.cur().unwrap().symbol())
+                    ));
                 }
             }
         }
     }
 
-    fn parse_open_tag<'a>(&self, ctx: &mut Context<'a>) -> ParseResult<TagBuilder<'a>> {
+    fn parse_open_tag<'a>(&self, ctx: &mut Context<'a>) -> CrimResult<TagBuilder<'a>> {
         let start_sym = ctx.cur().unwrap();
         let mut tb = TagBuilder::new(&start_sym);
 
         if ctx.next().is_some() {
             match ctx.cur().unwrap().symbol() {
                 SymbolType::View | SymbolType::Show | SymbolType::Loop |
+                SymbolType::If | SymbolType::ElseIf | SymbolType::Else |
                 SymbolType::Output => {
                     let name_sym = ctx.cur().unwrap();
                     ctx.next();
                     tb.set_name( name_sym );
                 }
                 _ => {
-                    return Err(ParseError{position: ctx.cur().unwrap().start().clone(), what: "Unexpected symbol".to_string()});
+                    return Err(CrimError::new(
+                        *ctx.cur().unwrap().start(),
+                        "Unexpected symbol".to_string()
+                    ));
                 }
             }
         } else {
-            return Err(ParseError::eos("tag type"));
+            return Err(CrimError::eos("tag type"));
         }
 
         self.parse_tag_params( ctx, &mut tb )?;
@@ -357,9 +324,9 @@ impl Parser {
                     tb.set_type( TagType::Unary );
                 }
                 _ => {
-                    return Err(ParseError::new(
-                        end_sym.start().clone(),
-                        format!("Unexpected symbol {:?} looking for end of tag.", end_sym.symbol()).as_str()
+                    return Err(CrimError::new(
+                        *end_sym.start(),
+                        format!("Unexpected symbol {:?} looking for end of tag.", end_sym.symbol())
                         ));
                 }
             }
@@ -370,31 +337,31 @@ impl Parser {
         Ok(tb)
     }
 
-    fn parse_end_tag<'a>(&self, ctx: &mut Context<'a> ) -> ParseResult<Symbol<'a>> {
+    fn parse_end_tag<'a>(&self, ctx: &mut Context<'a> ) -> CrimResult<Symbol<'a>> {
         if !ctx.cur().is("end tag",|s| *s == SymbolType::StartPoint )? {
-            return Err(ParseError{
-                position: *ctx.cur().unwrap().start(),
-                what: "Invalid end tag?".to_string(),
-            });
+            return Err(CrimError::new(
+                *ctx.cur().unwrap().start(),
+                "Invalid end tag?".to_string()
+            ));
         }
         if !ctx.next().is_valid_tag_name()? {
-            return Err(ParseError{
-                position: *ctx.cur().unwrap().start(),
-                what: "Invalid tag name".to_string(),
-            });
+            return Err(CrimError::new(
+                *ctx.cur().unwrap().start(),
+                "Invalid tag name".to_string()
+            ));
         }
         let name = ctx.cur().unwrap();
         if !ctx.next().is("end of end tag", |s| *s == SymbolType::EndFlat )? {
-            return Err(ParseError{
-                position: *ctx.cur().unwrap().start(),
-                what: "Tag should be <| |] style end tag.".to_string(),
-            });
+            return Err(CrimError::new(
+                *ctx.cur().unwrap().start(),
+                "Tag should be <| |] style end tag.".to_string(),
+            ));
         }
         ctx.next();
         Ok(name)
     }
 
-    fn parse_tag_body<'a>(&self, ctx: &mut Context<'a> ) -> ParseResult<TagBuilder<'a>> {
+    fn parse_tag_body<'a>(&self, ctx: &mut Context<'a> ) -> CrimResult<TagBuilder<'a>> {
         let mut tb = self.parse_open_tag( ctx )?;
         if tb.is_unary() {
             return Ok(tb);
@@ -402,7 +369,7 @@ impl Parser {
 
         loop {
             if ctx.cur().is_none() {
-                return Err(ParseError::eos(format!("close tag for {:?}", tb.name()).as_str()));
+                return Err(CrimError::eos(format!("close tag for {:?}", tb.name()).as_str()));
             }
             match ctx.cur().unwrap().symbol() {
                 SymbolType::Text(s) => {
@@ -419,29 +386,29 @@ impl Parser {
                         return Ok(tb);
                     } else {
                         // They don't match, complain.
-                        return Err(ParseError{
-                            position: *end.start(),
-                            what: "Mismatched open and closing tags.".to_string()
-                        });
+                        return Err(CrimError::new(
+                            *end.start(),
+                            "Mismatched open and closing tags.".to_string()
+                        ));
                     }
                 }
                 SymbolType::Error{..} => {
                     return self.lex_error( &ctx.cur().unwrap() );
                 }
                 _ => {
-                    return Err(ParseError{
-                        position: ctx.cur().unwrap().start().clone(),
-                        what: format!("Unexpected token: {:?}", ctx.cur().unwrap().symbol()),
-                    });
+                    return Err(CrimError::new(
+                        *ctx.cur().unwrap().start(),
+                        format!("Unexpected token: {:?}", ctx.cur().unwrap().symbol()),
+                    ));
                 }
             }
         }
     }
 
-    fn parse_tag_params(&self, ctx: &mut Context, tb: &mut TagBuilder ) -> ParseResult<()> {
+    fn parse_tag_params(&self, ctx: &mut Context, tb: &mut TagBuilder ) -> CrimResult<()> {
         loop {
             if ctx.cur().is_none() {
-                return Err(ParseError::eos("tag parameters"));
+                return Err(CrimError::eos("tag parameters"));
             }
             match ctx.cur().unwrap().symbol() {
                 SymbolType::Literal(s) => {
@@ -462,7 +429,7 @@ impl Parser {
         Ok(())
     }
 
-    fn parse_identifier(&self, ctx: &mut Context ) -> ParseResult<ParamValue> {
+    fn parse_identifier(&self, ctx: &mut Context ) -> CrimResult<ParamValue> {
         let mut id = Identifier::new();
 
         loop {
@@ -471,7 +438,7 @@ impl Parser {
                     id.push( IdentifierValue::Name(s.to_string()) );
                 }
             } else {
-                return Err(ParseError::new( ctx.cur().unwrap().start().clone(), &format!("Expeceted identifier, found {:?}", ctx.cur().unwrap().symbol() ) ) );
+                return Err(CrimError::new( ctx.cur().unwrap().start().clone(), format!("Expeceted identifier, found {:?}", ctx.cur().unwrap().symbol() ) ) );
             }
 
             if !ctx.next().is("identifier seperator",|s| *s == SymbolType::Period )? {
@@ -483,10 +450,10 @@ impl Parser {
         Ok(ParamValue::Identifier(id))
     }
     
-    fn parse_tag_props(&self, ctx: &mut Context, tb: &mut TagBuilder ) -> ParseResult<()> {
+    fn parse_tag_props(&self, ctx: &mut Context, tb: &mut TagBuilder ) -> CrimResult<()> {
         loop {
             if ctx.cur().is_none() {
-                return Err(ParseError::eos("tag properties"));
+                return Err(CrimError::eos("tag properties"));
             }
             if let SymbolType::Token(s) = ctx.cur().unwrap().symbol() {
                 if ctx.peek().is_some_and(|s|s.check_type(|t| matches!(t,SymbolType::Equals))) {
@@ -495,7 +462,7 @@ impl Parser {
                         let SymbolType::Literal(lv) = sym.symbol() {
                         tb.add_prop( s.to_string(), lv.to_string() );
                     } else {
-                        return Err(ParseError{position: Position::new(0,0), what: "Expected quoted literal string".to_string()});
+                        return Err(CrimError::new(Position::none(),"Expected quoted literal string".to_string()));
                     }
                 } else {
                     break;
@@ -607,13 +574,13 @@ impl<'a> TagBuilder<'a> {
         self.tag_type
     }
 
-    pub fn build_view(mut self, ctx: &Context, outputs: Vec<Output>) -> ParseResult<View> {
+    pub fn build_view(mut self, ctx: &Context, outputs: Vec<Output>) -> CrimResult<View> {
         if let Some(sym) = self.name {
             if *sym.symbol() == SymbolType::View {
                 let name = if let ParamValue::Literal(s) = self.params.swap_remove(0) {
                     s.to_string()
                 } else {
-                    return Err(ParseError::new(Position::none(), "Expected string literal for view name."));
+                    return Err(CrimError::new(Position::none(), "Expected string literal for view name.".to_string()));
                 };
                 Ok(View {
                     name: name,
@@ -623,41 +590,41 @@ impl<'a> TagBuilder<'a> {
                     layout: self.props.get("layout").cloned(),
                 })
             } else {
-                Err(ParseError::new(self.start_pos, &format!("Expected tag type view, found {:?}", sym.symbol())))
+                Err(CrimError::new(self.start_pos, format!("Expected tag type view, found {:?}", sym.symbol())))
            }
         } else {
-            Err(ParseError::new(self.start_pos, "Broken Parser? No tag type found when building view."))
+            Err(CrimError::new(self.start_pos, "Broken Parser? No tag type found when building view.".to_string()))
         }
     }
 
-    pub fn build_output(mut self) -> ParseResult<Output> {
+    pub fn build_output(mut self) -> CrimResult<Output> {
         if let Some(sym) = self.name {
             if *sym.symbol() == SymbolType::Output {
                 let name = if let ParamValue::Literal(s) = self.params.swap_remove(0) {
                     s.to_string()
                 } else {
-                    return Err(ParseError::new(Position::none(), "Expected string literal for output name."));
+                    return Err(CrimError::new(Position::none(), "Expected string literal for output name.".into()));
                 };
                 Ok(Output {
                     name: name,
                     code: self.children,
                 })
             } else {
-                Err(ParseError::new(self.start_pos, &format!("Expected tag type view, found {:?}", sym.symbol())))
+                Err(CrimError::new(self.start_pos, format!("Expected tag type view, found {:?}", sym.symbol())))
             }
         } else {
-            Err(ParseError::new(self.start_pos, "Broken Parser? No tag type found when building view."))
+            Err(CrimError::new(self.start_pos, "Broken Parser? No tag type found when building view.".into()))
         }
     }
 
-    pub fn build(mut self) -> ParseResult<Token> {
+    pub fn build(mut self) -> CrimResult<Token> {
         if let Some(sym) = self.name {
             match sym.symbol() {
                 SymbolType::Loop => {
                     let id = if let ParamValue::Identifier(id) = self.params.swap_remove(0) {
                         id
                     } else {
-                        return Err(ParseError::new(Position::none(), "Identifier for loop variable name."));
+                        return Err(CrimError::new(Position::none(), "Identifier for loop variable name.".into()));
                     };
                     Ok(Token::Loop(id, self.children))
                 }
@@ -665,22 +632,16 @@ impl<'a> TagBuilder<'a> {
                     let id = if let ParamValue::Identifier(id) = self.params.swap_remove(0) {
                         id
                     } else {
-                        return Err(ParseError::new(Position::none(), "Identifier for show variable name."));
+                        return Err(CrimError::new(Position::none(), "Identifier for show variable name.".into()));
                     };
                     Ok(Token::Show(id, self.props))
                 }
                 _ => {
-                    Err(ParseError {
-                        position: self.start_pos,
-                        what: "Bad tag type".to_string(),
-                    })
+                    Err(CrimError::new( self.start_pos, "Bad tag type".into()))
                 }
             }
         } else {
-            Err(ParseError {
-                position: self.start_pos,
-                what: "Bad tag type".to_string(),
-            })
+            Err(CrimError::new(self.start_pos, "Bad tag type".into()))
         }
     }
 }