Implement reset functionality on existing statements

mps-interpreter/src/lang/filter.rs

@@ -20,6 +20,10 @@ pub trait MpsFilterPredicate: Clone + Debug + Display {
         ctx: &mut MpsContext,
         op: &mut OpGetter,
     ) -> Result<bool, RuntimeError>;
+
+    fn is_complete(&self) -> bool;
+
+    fn reset(&mut self) -> Result<(), RuntimeError>;
 }
 
 pub trait MpsFilterFactory<P: MpsFilterPredicate + 'static> {
@@ -88,7 +92,7 @@ impl<P: MpsFilterPredicate + 'static> MpsOp for MpsFilterStatement<P> {
                 } else {
                     false
                 }
-            },
+            }
             VariableOrOp::Op(PseudoOp::Real(op)) => op.is_resetable(),
             VariableOrOp::Op(PseudoOp::Fake(_)) => false,
         }
@@ -96,10 +100,17 @@ impl<P: MpsFilterPredicate + 'static> MpsOp for MpsFilterStatement<P> {
 
     fn reset(&mut self) -> Result<(), RuntimeError> {
         let fake = PseudoOp::Fake(format!("{}", self));
+        self.predicate.reset()?;
         match &mut self.iterable {
             VariableOrOp::Variable(s) => {
                 let fake_getter = &mut move || fake.clone();
-                if let MpsType::Op(var) = self.context.as_mut().unwrap().variables.get_mut(s, fake_getter)? {
+                if let MpsType::Op(var) = self
+                    .context
+                    .as_mut()
+                    .unwrap()
+                    .variables
+                    .get_mut(s, fake_getter)?
+                {
                     var.reset()
                 } else {
                     Err(RuntimeError {
@@ -108,12 +119,12 @@ impl<P: MpsFilterPredicate + 'static> MpsOp for MpsFilterStatement<P> {
                         msg: "Cannot reset non-iterable filter variable".to_string(),
                     })
                 }
-            },
+            }
             VariableOrOp::Op(PseudoOp::Real(op)) => op.reset(),
             VariableOrOp::Op(PseudoOp::Fake(_)) => Err(RuntimeError {
                 line: 0,
                 op: fake,
-                        msg: "Cannot reset fake filter".to_string(),
+                msg: "Cannot reset PseudoOp::Fake filter".to_string(),
             }),
         }
     }
@@ -123,6 +134,9 @@ impl<P: MpsFilterPredicate + 'static> Iterator for MpsFilterStatement<P> {
     type Item = Result<MpsMusicItem, RuntimeError>;
 
     fn next(&mut self) -> Option<Self::Item> {
+        if self.predicate.is_complete() {
+            return None;
+        }
         let self_clone = self.clone();
         let self_clone2 = self_clone.clone();
         let mut op_getter = move || (Box::new(self_clone.clone()) as Box<dyn MpsOp>).into();

mps-interpreter/src/lang/operation.rs

@@ -3,8 +3,8 @@ use std::fmt::{Debug, Display};
 use std::iter::Iterator;
 
 use super::MpsLanguageDictionary;
-use super::{RuntimeError, SyntaxError};
 use super::PseudoOp;
+use super::{RuntimeError, SyntaxError};
 use crate::tokens::MpsToken;
 use crate::MpsContext;
 use crate::MpsMusicItem;
@@ -63,12 +63,17 @@ pub trait MpsOp: Iterator<Item = Result<MpsMusicItem, RuntimeError>> + Debug + D
 
     fn escape(&mut self) -> MpsContext;
 
-    fn is_resetable(&self) -> bool {false}
+    fn is_resetable(&self) -> bool {
+        false
+    }
 
     fn reset(&mut self) -> Result<(), RuntimeError> {
         #[cfg(debug_assertions)]
         if self.is_resetable() {
-            panic!("MpsOp reported that it can be reset but did not implement reset (op: {})", self)
+            panic!(
+                "MpsOp reported that it can be reset but did not implement reset (op: {})",
+                self
+            )
         }
         Err(RuntimeError {
             line: 0,

mps-interpreter/src/lang/pseudo_op.rs

@@ -51,6 +51,10 @@ impl PseudoOp {
             _ => false,
         }
     }
+
+    pub fn from_printable<D: Display + Debug>(item: &D) -> Self {
+        Self::Fake(format!("{}", item))
+    }
 }
 
 impl Clone for PseudoOp {

mps-interpreter/src/lang/vocabulary/files.rs

@@ -106,6 +106,16 @@ impl MpsOp for FilesStatement {
     fn escape(&mut self) -> MpsContext {
         self.context.take().unwrap()
     }
+
+    fn is_resetable(&self) -> bool {
+        true
+    }
+
+    fn reset(&mut self) -> Result<(), RuntimeError> {
+        self.has_tried = false;
+        self.file_iter = None;
+        Ok(())
+    }
 }
 
 pub struct FilesFunctionFactory;

mps-interpreter/src/lang/vocabulary/filters/empty_filter.rs

@@ -27,6 +27,14 @@ impl MpsFilterPredicate for EmptyFilter {
     ) -> Result<bool, RuntimeError> {
         Ok(true)
     }
+
+    fn is_complete(&self) -> bool {
+        false
+    }
+
+    fn reset(&mut self) -> Result<(), RuntimeError> {
+        Ok(())
+    }
 }
 
 pub struct EmptyFilterFactory;

mps-interpreter/src/lang/vocabulary/filters/field_filter.rs

@@ -77,6 +77,14 @@ impl MpsFilterPredicate for FieldFilter {
             })
         }
     }
+
+    fn is_complete(&self) -> bool {
+        false
+    }
+
+    fn reset(&mut self) -> Result<(), RuntimeError> {
+        Ok(())
+    }
 }
 
 pub struct FieldFilterFactory;
@@ -88,9 +96,9 @@ impl MpsFilterFactory<FieldFilter> for FieldFilterFactory {
             && tokens[0].is_name()
             && (tokens[1].is_open_angle_bracket() || tokens[1].is_close_angle_bracket())
             && (tokens[2].is_name() || check_is_type(&tokens[2])))
-            || (tokens_len == 4 // field >= variable OR field <= variable
+            || (tokens_len == 4 // field >= variable OR field <= variable OR field != variable
             && tokens[0].is_name()
-            && (tokens[1].is_open_angle_bracket() || tokens[1].is_close_angle_bracket() || tokens[1].is_equals())
+            && (tokens[1].is_open_angle_bracket() || tokens[1].is_close_angle_bracket() || tokens[1].is_equals() || tokens[1].is_exclamation())
             && tokens[2].is_equals()
             && (tokens[3].is_name() || check_is_type(&tokens[3])))
     }

mps-interpreter/src/lang/vocabulary/filters/utility.rs

@@ -74,6 +74,10 @@ pub fn assert_comparison_operator(tokens: &mut VecDeque<MpsToken>) -> Result<[i8
                 Ok([1, 1])
             }
         }
+        MpsToken::Exclamation => {
+            assert_token_raw(MpsToken::Equals, tokens)?;
+            Ok([-1, 1])
+        }
         _ => Err(SyntaxError {
             line: 0,
             token: MpsToken::Equals, // TODO this can be < > or =

mps-interpreter/src/lang/vocabulary/repeat.rs

@@ -20,6 +20,7 @@ pub struct RepeatStatement {
     cache_position: usize,
     repetitions: usize,
     loop_forever: bool,
+    original_repetitions: usize,
 }
 
 impl Display for RepeatStatement {
@@ -38,6 +39,7 @@ impl std::clone::Clone for RepeatStatement {
             cache_position: self.cache_position,
             repetitions: self.repetitions,
             loop_forever: self.loop_forever,
+            original_repetitions: self.original_repetitions,
         }
     }
 }
@@ -50,12 +52,12 @@ impl Iterator for RepeatStatement {
             Err(e) => return Some(Err(e)),
             Ok(real) => real,
         };
-        if real_op.is_resetable() {
         // give context to inner (should only occur on first run)
         if self.context.is_some() {
             let ctx = self.context.take().unwrap();
             real_op.enter(ctx);
         }
+        if real_op.is_resetable() {
             while self.loop_forever || !self.inner_done {
                 while let Some(item) = real_op.next() {
                     return Some(item);
@@ -69,14 +71,14 @@ impl Iterator for RepeatStatement {
                         self.repetitions -= 1;
                         match real_op.reset() {
                             Err(e) => return Some(Err(e)),
-                            Ok(_) => {},
+                            Ok(_) => {}
                         }
                     }
                 } else {
                     // always reset in infinite loop mode
                     match real_op.reset() {
                         Err(e) => return Some(Err(e)),
-                        Ok(_) => {},
+                        Ok(_) => {}
                     }
                 }
             }
@@ -151,6 +153,42 @@ impl MpsOp for RepeatStatement {
             self.inner_statement.try_real().unwrap().escape()
         }
     }
+
+    fn is_resetable(&self) -> bool {
+        true
+    }
+
+    fn reset(&mut self) -> Result<(), RuntimeError> {
+        let real_op = self.inner_statement.try_real()?;
+        if self.context.is_some() {
+            let ctx = self.context.take().unwrap();
+            real_op.enter(ctx);
+        }
+        if real_op.is_resetable() {
+            real_op.reset()?;
+            if self.original_repetitions == 0 {
+                self.repetitions = 0;
+                self.inner_done = true;
+            } else {
+                self.repetitions = self.original_repetitions - 1;
+                self.inner_done = false;
+            }
+        } else {
+            if self.inner_done {
+                self.repetitions = self.original_repetitions;
+                self.cache_position = 0;
+            } else {
+                return Err(RuntimeError {
+                    line: 0,
+                    op: PseudoOp::from_printable(self),
+                    msg:
+                        "Cannot reset part way through repeat when inner statement is not resetable"
+                            .to_string(),
+                });
+            }
+        }
+        Ok(())
+    }
 }
 
 pub struct RepeatFunctionFactory;
@@ -177,14 +215,17 @@ impl MpsFunctionFactory<RepeatStatement> for RepeatFunctionFactory {
             assert_token_raw(MpsToken::Comma, tokens)?;
             count = Some(assert_token(
                 |t| match t {
-                    MpsToken::Name(n) => n.parse::<usize>().map(
+                    MpsToken::Name(n) => n
-                        |d| if d == 0 {
+                        .parse::<usize>()
+                        .map(|d| {
+                            if d == 0 {
                                 inner_done = true;
                                 0
                             } else {
-                                d-1
+                                d - 1
                             }
-                    ).ok(),
+                        })
+                        .ok(),
                     _ => None,
                 },
                 MpsToken::Name("usize".into()),
@@ -199,6 +240,7 @@ impl MpsFunctionFactory<RepeatStatement> for RepeatFunctionFactory {
             cache_position: 0,
             repetitions: count.unwrap_or(0),
             loop_forever: count.is_none(),
+            original_repetitions: count.and_then(|c| Some(c + 1)).unwrap_or(0),
         })
     }
 }

mps-interpreter/src/lang/vocabulary/sql_query.rs

@@ -58,6 +58,16 @@ impl MpsOp for SqlStatement {
     fn escape(&mut self) -> MpsContext {
         self.context.take().unwrap()
     }
+
+    fn is_resetable(&self) -> bool {
+        true
+    }
+
+    fn reset(&mut self) -> Result<(), RuntimeError> {
+        self.rows = None;
+        self.current = 0;
+        Ok(())
+    }
 }
 
 impl std::clone::Clone for SqlStatement {
@@ -88,7 +98,7 @@ impl Iterator for SqlStatement {
                 Err(e) => {
                     self.rows = Some(Vec::with_capacity(0));
                     return Some(Err(e));
-                },
+                }
                 Ok(rows) => {
                     self.rows = Some(rows);
                     self.get_item(false)

mps-interpreter/src/lang/vocabulary/sql_simple_query.rs

@@ -107,6 +107,16 @@ impl MpsOp for SimpleSqlStatement {
     fn escape(&mut self) -> MpsContext {
         self.context.take().unwrap()
     }
+
+    fn is_resetable(&self) -> bool {
+        true
+    }
+
+    fn reset(&mut self) -> Result<(), RuntimeError> {
+        self.rows = None;
+        self.current = 0;
+        Ok(())
+    }
 }
 
 impl std::clone::Clone for SimpleSqlStatement {
@@ -150,7 +160,7 @@ impl Iterator for SimpleSqlStatement {
                 Err(e) => {
                     self.rows = Some(Vec::with_capacity(0));
                     return Some(Err(e));
-                },
+                }
                 Ok(rows) => {
                     self.rows = Some(rows);
                     self.get_item(false)

mps-interpreter/src/processing/filesystem.rs

@@ -1,5 +1,5 @@
 use std::fmt::{Debug, Display, Error, Formatter};
-use std::fs::{ReadDir, DirEntry};
+use std::fs::{DirEntry, ReadDir};
 use std::iter::Iterator;
 use std::path::{Path, PathBuf};
 
@@ -86,11 +86,16 @@ impl FileIter {
         };
         let dir_vec = if root_path.is_dir() {
             let mut vec = Vec::with_capacity(DEFAULT_VEC_CACHE_SIZE);
-            vec.push(root_path.read_dir().map_err(|e| RuntimeError {
+            vec.push(
+                root_path
+                    .read_dir()
+                    .map_err(|e| RuntimeError {
                         line: 0,
                         op: op(),
                         msg: format!("Directory read error: {}", e),
-            })?.into());
+                    })?
+                    .into(),
+            );
             vec
         } else {
             Vec::with_capacity(DEFAULT_VEC_CACHE_SIZE)
@@ -257,7 +262,7 @@ impl Iterator for FileIter {
                         Err(e) => {
                             self.is_complete = true;
                             return Some(Err(format!("Directory read error: {}", e)));
-                        },
+                        }
                     });
                     return self.next();
                 }

mps-interpreter/src/processing/variables.rs

@@ -69,7 +69,6 @@ pub struct MpsOpStorage {
 }
 
 impl MpsVariableStorer for MpsOpStorage {
-
     fn get_opt(&self, key: &str) -> Option<&MpsType> {
         self.storage.get(key)
     }

mps-interpreter/src/tokens/token_enum.rs

@@ -15,6 +15,8 @@ pub enum MpsToken {
     OpenAngleBracket,
     CloseAngleBracket,
     Dot,
+    Exclamation,
+    Interrogation,
 }
 
 impl MpsToken {
@@ -30,6 +32,8 @@ impl MpsToken {
             "<" => Ok(Self::OpenAngleBracket),
             ">" => Ok(Self::CloseAngleBracket),
             "." => Ok(Self::Dot),
+            "!" => Ok(Self::Exclamation),
+            "?" => Ok(Self::Interrogation),
             _ => {
                 // name validation
                 let mut ok = true;
@@ -138,6 +142,20 @@ impl MpsToken {
             _ => false,
         }
     }
+
+    pub fn is_exclamation(&self) -> bool {
+        match self {
+            Self::Exclamation => true,
+            _ => false,
+        }
+    }
+
+    pub fn is_interrogation(&self) -> bool {
+        match self {
+            Self::Interrogation => true,
+            _ => false,
+        }
+    }
 }
 
 impl Display for MpsToken {
@@ -156,6 +174,8 @@ impl Display for MpsToken {
             Self::OpenAngleBracket => write!(f, "<"),
             Self::CloseAngleBracket => write!(f, ">"),
             Self::Dot => write!(f, "."),
+            Self::Exclamation => write!(f, "!"),
+            Self::Interrogation => write!(f, "?"),
         }
     }
 }

mps-interpreter/src/tokens/tokenizer.rs

@@ -119,7 +119,10 @@ where
                     buf.clear();
                     return match invalid_char {
                         0 => Err(self.error(format!("EOF"))),
-                        _ => Err(self.error(format!("character {:?} ({})", invalid_char as char, invalid_char)))
+                        _ => Err(self.error(format!(
+                            "character {:?} ({})",
+                            invalid_char as char, invalid_char
+                        ))),
                     };
                 }
                 _ => {}

mps-interpreter/tests/single_line.rs

@@ -136,14 +136,24 @@ fn execute_emptyfilter_line() -> Result<(), Box<dyn MpsLanguageError>> {
 
 #[test]
 fn execute_fieldfilter_line() -> Result<(), Box<dyn MpsLanguageError>> {
-    execute_single_line("song(`lov`).(year >= 2020)", false, true)
+    execute_single_line(
+        "files(`~/Music/MusicFlac/Bruno Mars/24K Magic/`).(year >= 2000)",
+        false,
+        true,
+    )
 }
 
 #[test]
 fn execute_files_line() -> Result<(), Box<dyn MpsLanguageError>> {
     execute_single_line(
-        r"files(`~/Music/MusicFlac/Bruno Mars/24K Magic/`, re=``, recursive=false)",
+        r"files(folder=`~/Music/MusicFlac/Bruno Mars/24K Magic/`, re=``, recursive=false)",
         false,
         true,
-    )
+    )?;
+    execute_single_line(
+        r"files(`~/Music/MusicFlac/Bruno Mars/24K Magic/`)",
+        false,
+        true,
+    )?;
+    execute_single_line(r"files()", false, true)
 }