5 files changed, 238 insertions, 50 deletions

diff --git a/Cargo.lock b/Cargo.lock
index de51705..287db82 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,5 +1,7 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+version = 3
+
 [[package]]
 name = "aho-corasick"
 version = "0.7.10"
@@ -55,9 +57,9 @@ checksum = "b41b7ea54a0c9d92199de89e20e58d49f02f8e699814ef3fdf266f6f748d15c7"
 
 [[package]]
 name = "bitflags"
-version = "1.2.1"
+version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
 [[package]]
 name = "blake2b_simd"
@@ -83,6 +85,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 
 [[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
 name = "clap"
 version = "2.33.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -98,6 +106,17 @@ dependencies = [
 ]
 
 [[package]]
+name = "clipboard-win"
+version = "4.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3db8340083d28acb43451166543b98c838299b7e0863621be53a338adceea0ed"
+dependencies = [
+ "error-code",
+ "str-buf",
+ "winapi",
+]
+
+[[package]]
 name = "constant_time_eq"
 version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -110,7 +129,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c3c7c73a2d1e9fc0886a08b93e98eb643461230d5f1925e4036204d5f2e261a8"
 dependencies = [
  "autocfg",
- "cfg-if",
+ "cfg-if 0.1.10",
  "lazy_static",
 ]
 
@@ -120,31 +139,36 @@ version = "2.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "551a778172a450d7fc12e629ca3b0428d00f6afa9a43da1b630d54604e97371c"
 dependencies = [
- "cfg-if",
+ "cfg-if 0.1.10",
  "dirs-sys",
 ]
 
 [[package]]
-name = "dirs"
-version = "1.0.5"
+name = "dirs-sys"
+version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fd78930633bd1c6e35c4b42b1df7b0cbc6bc191146e512bb3bedf243fcc3901"
+checksum = "afa0b23de8fd801745c471deffa6e12d248f962c9fd4b4c33787b055599bde7b"
 dependencies = [
+ "cfg-if 0.1.10",
  "libc",
  "redox_users",
  "winapi",
 ]
 
 [[package]]
-name = "dirs-sys"
-version = "0.3.4"
+name = "endian-type"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "afa0b23de8fd801745c471deffa6e12d248f962c9fd4b4c33787b055599bde7b"
+checksum = "c34f04666d835ff5d62e058c3995147c06f42fe86ff053337632bca83e42702d"
+
+[[package]]
+name = "error-code"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5115567ac25674e0043e472be13d14e537f37ea8aa4bdc4aef0c89add1db1ff"
 dependencies = [
- "cfg-if",
  "libc",
- "redox_users",
- "winapi",
+ "str-buf",
 ]
 
 [[package]]
@@ -162,12 +186,23 @@ dependencies = [
 ]
 
 [[package]]
+name = "fd-lock"
+version = "3.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a16910e685088843d53132b04e0f10a571fdb193224fc589685b3ba1ce4cb03d"
+dependencies = [
+ "cfg-if 1.0.0",
+ "libc",
+ "windows-sys",
+]
+
+[[package]]
 name = "getrandom"
 version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7abc8dd8451921606d809ba32e95b6111925cd2906060d2dcc29c070220503eb"
 dependencies = [
- "cfg-if",
+ "cfg-if 0.1.10",
  "libc",
  "wasi",
 ]
@@ -189,9 +224,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.68"
+version = "0.2.112"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dea0c0405123bba743ee3f91f49b1c7cfb684eef0da0a50110f758ccf24cdff0"
+checksum = "1b03d17f364a3a042d5e5d46b053bbbf82c92c9430c592dd4c064dc6ee997125"
 
 [[package]]
 name = "log"
@@ -199,7 +234,7 @@ version = "0.4.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "14b6052be84e6b71ab17edffc2eeabf5c2c3ae1fdb464aae35ac50c67a44e1f7"
 dependencies = [
- "cfg-if",
+ "cfg-if 0.1.10",
 ]
 
 [[package]]
@@ -209,16 +244,34 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3728d817d99e5ac407411fa471ff9800a778d88a24685968b36824eaf4bee400"
 
 [[package]]
+name = "memoffset"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5aa361d4faea93603064a027415f07bd8e1d5c88c9fbf68bf56a285428fd79ce"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "nibble_vec"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a5d83df9f36fe23f0c3648c6bbb8b0298bb5f1939c8f2704431371f4b84d43"
+dependencies = [
+ "smallvec",
+]
+
+[[package]]
 name = "nix"
-version = "0.13.1"
+version = "0.23.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4dbdc256eaac2e3bd236d93ad999d3479ef775c863dbda3068c4006a92eec51b"
+checksum = "9f866317acbd3a240710c63f065ffb1e4fd466259045ccb504130b7f668f35c6"
 dependencies = [
  "bitflags",
  "cc",
- "cfg-if",
+ "cfg-if 1.0.0",
  "libc",
- "void",
+ "memoffset",
 ]
 
 [[package]]
@@ -305,6 +358,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ce082a9940a7ace2ad4a8b7d0b1eac6aa378895f18be598230c5f2284ac05426"
 
 [[package]]
+name = "radix_trie"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c069c179fcdc6a2fe24d8d18305cf085fdbd4f922c041943e203685d6a1c58fd"
+dependencies = [
+ "endian-type",
+ "nibble_vec",
+]
+
+[[package]]
 name = "redox_syscall"
 version = "0.1.56"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -353,15 +416,21 @@ dependencies = [
 
 [[package]]
 name = "rustyline"
-version = "4.1.0"
+version = "9.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0f47ea1ceb347d2deae482d655dc8eef4bd82363d3329baffa3818bd76fea48b"
+checksum = "6c38cfbd0a4d7df7aab7cf53732d5d43449d0300358fd15cd4e8c8468a956aca"
 dependencies = [
- "dirs",
+ "bitflags",
+ "cfg-if 1.0.0",
+ "clipboard-win",
+ "fd-lock",
  "libc",
  "log",
  "memchr",
  "nix",
+ "radix_trie",
+ "scopeguard",
+ "smallvec",
  "unicode-segmentation",
  "unicode-width",
  "utf8parse",
@@ -369,6 +438,24 @@ dependencies = [
 ]
 
 [[package]]
+name = "scopeguard"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
+
+[[package]]
+name = "smallvec"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ecab6c735a6bb4139c0caafd0cc3635748bbb3acf4550e8138122099251f309"
+
+[[package]]
+name = "str-buf"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d44a3643b4ff9caf57abcee9c2c621d6c03d9135e0d8b589bd9afb5992cb176a"
+
+[[package]]
 name = "strsim"
 version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -416,9 +503,9 @@ checksum = "caaa9d531767d1ff2150b9332433f32a24622147e5ebb1f26409d5da67afd479"
 
 [[package]]
 name = "utf8parse"
-version = "0.1.1"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8772a4ccbb4e89959023bc5b7cb8623a795caa7092d99f3aa9501b9484d4557d"
+checksum = "936e4b492acfd135421d8dca4b1aa80a7bfc26e702ef3af710e0752684df5372"
 
 [[package]]
 name = "vec_map"
@@ -427,12 +514,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
 
 [[package]]
-name = "void"
-version = "1.0.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
-
-[[package]]
 name = "wasi"
 version = "0.9.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -459,3 +540,46 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
+[[package]]
+name = "windows-sys"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "82ca39602d5cbfa692c4b67e3bcbb2751477355141c1ed434c94da4186836ff6"
+dependencies = [
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52695a41e536859d5308cc613b4a022261a274390b25bd29dfff4bf08505f3c2"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f54725ac23affef038fecb177de6c9bf065787c2f432f79e3c373da92f3e1d8a"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51d5158a43cc43623c0729d1ad6647e62fa384a3d135fd15108d37c683461f64"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc31f409f565611535130cfe7ee8e6655d3fa99c1c61013981e491921b5ce954"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f2b8c7cbd3bfdddd9ab98769f9746a7fad1bca236554cd032b78d768bc0e89f"
diff --git a/Cargo.toml b/Cargo.toml
index 4527862..4be652d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,7 +12,7 @@ categories = ["command-line-interface", "science", "parser-implementations"]
 license = "MIT"
 
 [dependencies]
-rustyline   = "4.1.0"
+rustyline   = { version = "9.1.1", default-features = false }
 clap        = "2.32.0"
 radix_fmt   = "1.0.0"
 lazy_static = "1.3.0"
diff --git a/src/lex.rs b/src/lex.rs
index 76f61a0..1220a1f 100644
--- a/src/lex.rs
+++ b/src/lex.rs
@@ -101,6 +101,9 @@ lazy_static! {
         m.insert("acsc",  Function::token_from_fn("acsc".into(),  |x| (1./x).asin()));
         m.insert("asec",  Function::token_from_fn("asec".into(),  |x| (1./x).acos()));
         m.insert("acot",  Function::token_from_fn("acot".into(),  |x| (1./x).atan()));
+        m.insert("exp",   Function::token_from_fn("exp".into(),   |x| x.exp()));
+        m.insert("exp2",  Function::token_from_fn("exp2".into(),  |x| x.exp2()));
+        m.insert("round", Function::token_from_fn("round".into(), |x| x.round()));
         // single arg function s can be added here
         m
     };
@@ -134,19 +137,29 @@ pub fn lexer(input: &str, prev_ans: Option<f64>) -> Result<Vec<Token>, CalcError
             '0'..='9' | '.' => {
                 if !char_vec.is_empty() {
                     if FUNCTIONS.get(&char_vec[..]).is_some() {
-                        return Err(CalcError::Syntax(format!(
-                            "Function '{}' expected parentheses",
-                            char_vec
-                        )));
+                        char_vec.push(letter);
+                        if !FUNCTIONS.get(&char_vec[..]).is_some() {
+                            return Err(CalcError::Syntax(format!(
+                                "Function '{}' expected parentheses",
+                                &char_vec[..char_vec.chars().count()-1]
+                            )));
+                        }
+                    } else if CONSTANTS.get(&char_vec[..]).is_some() {
+                        result.push(CONSTANTS.get(&char_vec[..]).unwrap().clone());
+                        result.push(OPERATORS.get(&'*').unwrap().clone());
+                        char_vec.clear();
+                        num_vec.push(letter);
+                        last_char_is_op = false;
                     } else {
                         return Err(CalcError::Syntax(format!(
                             "Unexpected character '{}'",
                             char_vec
                         )));
                     }
+                } else {
+                    num_vec.push(letter);
+                    last_char_is_op = false;
                 }
-                num_vec.push(letter);
-                last_char_is_op = false;
             }
             '_' => {
                 if prev_ans.is_none() {
diff --git a/src/main.rs b/src/main.rs
index 75c33bb..e6a865e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -259,4 +259,35 @@ mod tests {
         let evaled = eval_math_expression("9 + _ ", Some(0f64)).unwrap();
         assert_eq!(9., evaled);
     }
+    #[test]
+    fn eval_const_multiplication() {
+        let evaled = eval_math_expression("e2", None).unwrap();
+        assert_eq!(5.4365636569, evaled);
+    }
+    #[test]
+    fn eval_round() {
+        let evaled = eval_math_expression("round(0.5)+round(2.4)", None).unwrap();
+        assert_eq!(3., evaled);
+    }
+    #[test]
+    fn eval_exp2() {
+        assert_eq!(
+            256.,
+            eval_math_expression("exp2(8)", None).unwrap()
+        );
+    }
+    #[test]
+    fn eval_exp() {
+        assert_eq!(
+            20.0855369232 as f64,
+            eval_math_expression("exp(3)", None).unwrap()
+        );
+    }
+    #[test]
+    fn eval_e_times_n() {
+        assert_eq!(
+            0. as f64,
+            eval_math_expression("e0", None).unwrap()
+        );
+    }
 }
diff --git a/src/readline.rs b/src/readline.rs
index d689f95..8906a4f 100644
--- a/src/readline.rs
+++ b/src/readline.rs
@@ -7,6 +7,7 @@ use rustyline::error::ReadlineError;
 use rustyline::highlight::Highlighter;
 use rustyline::hint::{Hinter, HistoryHinter};
 use rustyline::{Context, Editor, Helper};
+use rustyline::validate::Validator;
 
 use directories::ProjectDirs;
 
@@ -14,6 +15,7 @@ use regex::Regex;
 
 use crate::error::CalcError;
 use crate::eval_math_expression;
+use crate::lex::{CONSTANTS, FUNCTIONS};
 
 pub struct RLHelper {
     completer: FilenameCompleter,
@@ -51,20 +53,34 @@ impl Highlighter for LineHighlighter {
         let op = eval_math_expression(line, prev_ans);
         match op {
             Ok(_) => {
-                let constants = ["e", "pi"];
-                let functions = [
-                    "sin", "cos", "tan", "csc", "sec", "cot", "sinh", "cosh", "tanh", "ln", "log",
-                    "sqrt", "ceil", "floor", "rad", "deg", "abs", "asin", "acos", "atan", "acsc",
-                    "asec", "acot",
-                ];
+                let constants = CONSTANTS.keys();
+                let functions = FUNCTIONS.keys();
                 let ops = Regex::new(r"(?P<o>[\+-/\*%\^!])").unwrap();
                 let mut coloured: String = ops.replace_all(line, "\x1b[35m$o\x1b[0m").into();
 
-                for c in &constants {
-                    coloured = coloured.replace(c, &format!("\x1b[33m{}\x1b[0m", c));
+                for c in constants {
+                    // This regex consists of the following pieces:
+                    // * the constant (`o`) to highlight (to be substituted as `{}` via `format!`),
+                    //   e.g. `e`  or `pi`.
+                    // * (optionally) an ANSI escape-code (`\x1b\[35m`) that is used to highlight
+                    //   a binary operator (e.g. `+`/`-`/...). With this one it is ensured that
+                    //   binary operators are always correctly detected after a constant
+                    //   (see the next bullet-point for why that's needed).
+                    // * the following operator (e.g. `+`/`-`/...), a space or the end
+                    //   of the expression (to highlight e.g. `1+e` correctly). This is
+                    //   required to distinguish a constant in an expression from a function-call,
+                    //   e.g. `e+1` from `exp(1)`, without this matching logic, the `e` from
+                    //   `exp` would be improperly interpreted as constant.
+                    //
+                    // To make sure none of existing highlighting (i.e. highlighting
+                    // of binary operators that happens before) breaks, the escape-codes & operator
+                    // (called `r`) are appended after the highlighted constant.
+                    let re = Regex::new(format!("(?P<o>{})(?P<r>(\x1b\\[35m)?([\\+-/\\*%\\^! ]|$))", c).as_str()).unwrap();
+                    coloured = re.replace_all(&coloured, "\x1b[33m$o\x1b[0m$r").into();
                 }
-                for f in &functions {
-                    coloured = coloured.replace(f, &format!("\x1b[34m{}\x1b[0m", f));
+                for f in functions {
+                    let re = Regex::new(format!("(?P<o>{})(?P<r>(\\(|$))", f).as_str()).unwrap();
+                    coloured = re.replace_all(&coloured, "\x1b[34m$o\x1b[0m$r").into();
                 }
                 Owned(coloured)
             }
@@ -75,6 +91,7 @@ impl Highlighter for LineHighlighter {
 }
 
 impl Highlighter for RLHelper {
+    fn highlight_char(&self, _: &str, _: usize) -> bool { true }
     fn highlight_hint<'h>(&self, hint: &'h str) -> Cow<'h, str> {
         self.highlighter.highlight_hint(hint)
     }
@@ -96,11 +113,14 @@ impl Completer for RLHelper {
 }
 
 impl Hinter for RLHelper {
-    fn hint(&self, line: &str, a: usize, b: &Context) -> Option<String> {
+    type Hint = String;
+    fn hint(&self, line: &str, a: usize, b: &Context) -> Option<Self::Hint> {
         self.hinter.hint(line, a, b)
     }
 }
 
+impl Validator for RLHelper {}
+
 impl Helper for RLHelper {}
 
 pub fn create_readline() -> Editor<RLHelper> {