fix some edge cases in parser

mers/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mers"
-version = "0.8.16"
+version = "0.8.20"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "dynamically typed but type-checked programming language"
@@ -15,7 +15,7 @@ default = ["colored-output"]
 colored-output = ["mers_lib/ecolor-term", "mers_lib/pretty-print", "dep:colored"]
 
 [dependencies]
-mers_lib = "0.8.16"
+mers_lib = "0.8.20"
 # mers_lib = { path = "../mers_lib" }
 clap = { version = "4.3.19", features = ["derive"] }
 colored = { version = "2.1.0", optional = true }

mers_lib/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mers_lib"
-version = "0.8.19"
+version = "0.8.20"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "library to use the mers language in other projects"

mers_lib/src/errors/mod.rs

@@ -81,6 +81,7 @@ pub enum EColor {
     AsTypeTypeAnnotation,
     BadCharInTupleType,
     BadCharInFunctionType,
+    BadCharAtStartOfStatement,
     BadTypeFromParsed,
     TypeAnnotationNoClosingBracket,
     TryBadSyntax,

mers_lib/src/errors/themes.rs

@@ -70,8 +70,7 @@ pub fn default_theme<C>(
         UnknownVariable => hard_err,
         BackslashEscapeUnknown => hard_err,
         BackslashEscapeEOF | StringEOF | TypeEOF => missing,
-        BadCharInTupleType => hard_err,
-        BadCharInFunctionType => hard_err,
+        BadCharInTupleType | BadCharInFunctionType | BadCharAtStartOfStatement => hard_err,
         TryBadSyntax => hard_err,
         TypeAnnotationNoClosingBracket | BracketedRefTypeNoClosingBracket => missing,
 

mers_lib/src/parsing/statements.rs

@@ -112,6 +112,7 @@ pub fn parse(
         return Ok(None);
     };
     let mut pos_after_first = src.get_pos();
+    loop {
         src.skip_whitespace();
         match src.peek_word_allow_colon() {
             ":=" => {
@@ -127,6 +128,7 @@ pub fn parse(
                     target: first,
                     source,
                 });
+                break;
             }
             "=" => {
                 let pos_in_src = src.get_pos();
@@ -144,6 +146,7 @@ pub fn parse(
                     target: first,
                     source,
                 });
+                break;
             }
             "->" => {
                 let pos_in_src = src.get_pos();
@@ -162,9 +165,10 @@ pub fn parse(
                     arg: first,
                     run,
                 });
+                break;
+            }
+            _ => (),
         }
-        _ => loop {
-            src.skip_whitespace();
         let dot_in_src = src.get_pos();
         if let Some('.') = src.peek_char() {
             src.next_char();
@@ -218,7 +222,6 @@ pub fn parse(
             src.set_pos(pos_after_first);
             break;
         }
-        },
     }
     if matches!(src.peek_char(), Some(',' | ';')) {
         src.next_char();
@@ -495,15 +498,17 @@ pub fn parse_no_chain(
             pos_in_src: (pos_in_src, src.get_pos(), srca).into(),
             data: Data::new(crate::data::bool::Bool(false)),
         }),
-        "" => return Ok(None),
-        o => {
+        o if !o.trim().is_empty() => {
             let o = o.to_string();
             src.section_begin("literals, variables, and other non-keyword things".to_string());
             if let Ok(n) = o.parse() {
                 if src.peek_char() == Some('.') {
                     let here = src.get_pos();
                     src.next_char();
-                    if let Ok(num) = format!("{o}.{}", src.next_word()).parse() {
+                    let after_dot = src.next_word();
+                    if let Some(Ok(num)) =
+                        (!after_dot.is_empty()).then_some(format!("{o}.{}", after_dot).parse())
+                    {
                         Box::new(program::parsed::value::Value {
                             pos_in_src: (pos_in_src, src.get_pos(), srca).into(),
                             data: Data::new(crate::data::float::Float(num)),
@@ -546,6 +551,21 @@ pub fn parse_no_chain(
                 }
             }
         }
+        // empty string (after calling .trim())
+        _ => {
+            if src.next_char().is_some() {
+                // unexpected word-separator character
+                return Err(CheckError::new()
+                    .src(vec![(
+                        (pos_in_src, src.get_pos(), srca).into(),
+                        Some(EColor::BadCharAtStartOfStatement),
+                    )])
+                    .msg_str("Unexpected character found at the start of a statement".to_owned()));
+            } else {
+                // EOF
+                return Ok(None);
+            }
+        }
     }))
 }