diff --git a/src/custom_syntax.rs b/src/api/custom_syntax.rs
similarity index 100%
rename from src/custom_syntax.rs
rename to src/api/custom_syntax.rs
diff --git a/src/api/mod.rs b/src/api/mod.rs
index 13c5488a..e42a489a 100644
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -18,6 +18,8 @@ pub mod limits;
 
 pub mod events;
 
+pub mod custom_syntax;
+
 pub mod deprecated;
 
 use crate::engine::Precedence;
diff --git a/src/engine.rs b/src/engine.rs
index e4306199..121101fb 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -1,7 +1,7 @@
 //! Main module defining the script evaluation [`Engine`].
 
+use crate::api::custom_syntax::CustomSyntax;
 use crate::ast::{Expr, FnCallExpr, Ident, OpAssignment, Stmt, AST_OPTION_FLAGS::*};
-use crate::custom_syntax::CustomSyntax;
 use crate::func::native::{OnDebugCallback, OnParseTokenCallback, OnPrintCallback, OnVarCallback};
 use crate::func::{get_hasher, CallableFunction, IteratorFn};
 use crate::module::Namespace;
diff --git a/src/lib.rs b/src/lib.rs
index 67baf76d..b74cb0d4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -70,7 +70,6 @@ use std::prelude::v1::*;
 
 mod api;
 mod ast;
-mod custom_syntax;
 mod engine;
 mod func;
 mod module;
@@ -140,8 +139,8 @@ pub type FLOAT = f32;
 pub type ExclusiveRange = std::ops::Range<INT>;
 pub type InclusiveRange = std::ops::RangeInclusive<INT>;
 
+pub use api::custom_syntax::Expression;
 pub use ast::{FnAccess, AST};
-pub use custom_syntax::Expression;
 pub use engine::{
     Engine, EvalContext, OP_CONTAINS, OP_EQUALS, OP_EXCLUSIVE_RANGE, OP_INCLUSIVE_RANGE,
 };
diff --git a/src/parser.rs b/src/parser.rs
index a9d1ab8d..a29c65d9 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -1,11 +1,11 @@
 //! Main module defining the lexer and parser.
 
+use crate::api::custom_syntax::{markers::*, CustomSyntax};
 use crate::api::options::LanguageOptions;
 use crate::ast::{
     BinaryExpr, CustomExpr, Expr, FnCallExpr, FnCallHashes, Ident, OpAssignment, ScriptFnDef, Stmt,
     StmtBlock, AST_OPTION_FLAGS::*,
 };
-use crate::custom_syntax::{markers::*, CustomSyntax};
 use crate::engine::{Precedence, KEYWORD_THIS, OP_CONTAINS};
 use crate::func::hashing::get_hasher;
 use crate::module::Namespace;
@@ -2190,24 +2190,19 @@ fn parse_custom_syntax(
                 }
             },
             #[cfg(not(feature = "no_float"))]
-            crate::custom_syntax::markers::CUSTOM_SYNTAX_MARKER_FLOAT => {
-                match input.next().expect(NEVER_ENDS) {
-                    (Token::FloatConstant(f), pos) => {
-                        inputs.push(Expr::FloatConstant(f, pos));
-                        segments.push(f.to_string().into());
-                        tokens.push(state.get_identifier(
-                            "",
-                            crate::custom_syntax::markers::CUSTOM_SYNTAX_MARKER_FLOAT,
-                        ));
-                    }
-                    (_, pos) => {
-                        return Err(PERR::MissingSymbol(
-                            "Expecting a floating-point number".to_string(),
-                        )
-                        .into_err(pos))
-                    }
+            CUSTOM_SYNTAX_MARKER_FLOAT => match input.next().expect(NEVER_ENDS) {
+                (Token::FloatConstant(f), pos) => {
+                    inputs.push(Expr::FloatConstant(f, pos));
+                    segments.push(f.to_string().into());
+                    tokens.push(state.get_identifier("", CUSTOM_SYNTAX_MARKER_FLOAT));
                 }
-            }
+                (_, pos) => {
+                    return Err(PERR::MissingSymbol(
+                        "Expecting a floating-point number".to_string(),
+                    )
+                    .into_err(pos))
+                }
+            },
             CUSTOM_SYNTAX_MARKER_STRING => match input.next().expect(NEVER_ENDS) {
                 (Token::StringConstant(s), pos) => {
                     let s: ImmutableString = state.get_identifier("", s).into();