parser

src/utils.rs

@@ -0,0 +1,160 @@
+//! Until macros
+
+#[macro_export]
+macro_rules! expect {
+    ($src:ident, $index:expr, $expect:tt) => {
+        if $index >= $src.len() || $src.as_bytes()[$index] != $expect {
+            return None;
+        }
+    };
+    ($src:ident, $index:expr, $expect:expr) => {
+        if $index >= $src.len() || !$expect($src.as_bytes()[$index]) {
+            return None;
+        }
+    };
+}
+
+#[macro_export]
+macro_rules! eol {
+    ($src:expr) => {{
+        let mut pos = 0;
+        while pos < $src.len() {
+            if $src.as_bytes()[pos] == b'\n' {
+                break;
+            }
+            pos += 1;
+        }
+        pos
+    }};
+}
+
+#[macro_export]
+macro_rules! until {
+    ($src:expr, $until:tt) => {{
+        let mut pos = 0;
+        while pos < $src.len() {
+            if $until == $src.as_bytes()[pos] {
+                break;
+            }
+            pos += 1;
+        }
+        if pos == $src.len() {
+            None
+        } else {
+            Some(pos)
+        }
+    }};
+    ($src:expr, $until:expr) => {{
+        let mut pos = 0;
+        while pos < $src.len() {
+            if $until($src.as_bytes()[pos]) {
+                break;
+            }
+            pos += 1;
+        }
+        if pos == $src.len() {
+            None
+        } else {
+            Some(pos)
+        }
+    }};
+}
+
+#[macro_export]
+macro_rules! until_while {
+    ($src:expr, $start:expr, $until:tt, $while:expr) => {{
+        let mut pos = $start;
+        while pos < $src.len() {
+            // println!("pos {} char {} ", pos, $src.as_bytes()[pos] as char,);
+            if $until == $src.as_bytes()[pos] {
+                break;
+            } else if $while($src.as_bytes()[pos]) {
+                pos += 1;
+                continue;
+            } else {
+                return None;
+            }
+        }
+        if pos == $src.len() {
+            return None;
+        } else {
+            pos
+        }
+    }};
+    ($src:expr, $start:expr, $until:expr, $while:expr) => {{
+        let mut pos = $start;
+        while pos < $src.len() {
+            // println!("pos {} char {}", pos, $src.as_bytes()[pos] as char);
+            if $until($src.as_bytes()[pos]) {
+                break;
+            } else if $while($src.as_bytes()[pos]) {
+                pos += 1;
+                continue;
+            } else {
+                return None;
+            }
+        }
+        if pos == $src.len() {
+            return None;
+        } else {
+            pos
+        }
+    }};
+}
+
+#[macro_export]
+macro_rules! cond_eq {
+    ($s:ident, $i:expr, $p:expr) => {
+        if $i > $s.len() {
+            return None;
+        } else {
+            $s.as_bytes()[$i] == $p
+        }
+    };
+}
+
+#[macro_export]
+macro_rules! position {
+    ($s:ident, $i:expr, $p:expr) => {
+        match $s[$i..].chars().position($p) {
+            Some(x) => x + $i,
+            None => return None,
+        }
+    };
+}
+
+#[macro_export]
+macro_rules! find {
+    ($s:ident, $i:expr, $p:expr) => {
+        match $s[$i..].find($p) {
+            Some(x) => x + $i,
+            None => return None,
+        }
+    };
+}
+
+#[macro_export]
+macro_rules! starts_with {
+    ($s:ident, $p:expr) => {
+        if !$s.starts_with($p) {
+            return None;
+        }
+    };
+}
+
+#[macro_export]
+macro_rules! next_line {
+    ($s:ident, $p:expr) => {
+        self.chars().position(|c| c == ch).unwrap_or(self.len())
+        if !$s.starts_with($p) {
+            return None;
+        }
+    };
+}
+
+#[macro_export]
+macro_rules! skip_whitespace {
+    ($src:ident, $from:ident) => {
+        until!($src[$from..], |c| c != b' ').unwrap_or(0) + $from
+    };
+}