add int function

dsc_lib/Cargo.toml

@@ -8,6 +8,7 @@ base64 = "0.21"
 derive_builder ="0.20"
 indicatif = { version = "0.17" }
 jsonschema = "0.17"
+num-traits = "0.2"
 regex = "1.7"
 reqwest = { version = "0.11", features = ["blocking"] }
 schemars = { version = "0.8.12", features = ["preserve_order"] }

dsc_lib/src/dscerror.rs

@@ -23,6 +23,9 @@ pub enum DscError {
     #[error("Function '{0}' error: {1}")]
     Function(String, String),
 
+    #[error("Function '{0}' error: {1}")]
+    FunctionArg(String, String),
+
     #[error("HTTP: {0}")]
     Http(#[from] reqwest::Error),
 

dsc_lib/src/functions/int.rs

@@ -0,0 +1,83 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+use crate::DscError;
+use crate::configure::context::Context;
+use crate::functions::AcceptedArgKind;
+use num_traits::cast::NumCast;
+use serde_json::Value;
+use super::Function;
+
+#[derive(Debug, Default)]
+pub struct Int {}
+
+impl Function for Int {
+    fn accepted_arg_types(&self) -> Vec<AcceptedArgKind> {
+        vec![AcceptedArgKind::String, AcceptedArgKind::Number]
+    }
+
+    fn min_args(&self) -> usize {
+        1
+    }
+
+    fn max_args(&self) -> usize {
+        1
+    }
+
+    fn invoke(&self, args: &[Value], _context: &Context) -> Result<Value, DscError> {
+        let arg = &args[0];
+        let value: i64;
+        if arg.is_string() {
+            let input = arg.as_str().ok_or(DscError::FunctionArg("int".to_string(), "invalid input string".to_string()))?;
+            let result = input.parse::<f64>().map_err(|_| DscError::FunctionArg("int".to_string(), "unable to parse string to int".to_string()))?;
+            value = NumCast::from(result).ok_or(DscError::FunctionArg("int".to_string(), "unable to cast to int".to_string()))?;
+        } else if arg.is_number() {
+            value = arg.as_i64().ok_or(DscError::FunctionArg("int".to_string(), "unable to parse number to int".to_string()))?;
+        } else {
+            return Err(DscError::FunctionArg("int".to_string(), "Invalid argument type".to_string()));
+        }
+        Ok(Value::Number(value.into()))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::configure::context::Context;
+    use crate::parser::Statement;
+    use crate::DscError;
+
+    #[test]
+    fn string() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[int('4')]", &Context::new()).unwrap();
+        assert_eq!(result, 4);
+    }
+
+    #[test]
+    fn string_with_decimal() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[int('4.0')]", &Context::new()).unwrap();
+        assert_eq!(result, 4);
+    }
+
+    #[test]
+    fn number() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[int(123)]", &Context::new()).unwrap();
+        assert_eq!(result, 123);
+    }
+
+    #[test]
+    fn nested() {
+        let mut parser = Statement::new().unwrap();
+        let result = parser.parse_and_execute("[int(int('-1'))]", &Context::new()).unwrap();
+        assert_eq!(result, -1);
+    }
+
+    #[test]
+    fn error() {
+        let mut parser = Statement::new().unwrap();
+        let err = parser.parse_and_execute("[int('foo')]", &Context::new()).unwrap_err();
+        assert!(matches!(err, DscError::FunctionArg(_, _)));
+    }
+}

dsc_lib/src/functions/mod.rs

@@ -13,6 +13,7 @@ pub mod concat;
 pub mod create_array;
 pub mod div;
 pub mod envvar;
+pub mod int;
 pub mod max;
 pub mod min;
 pub mod mod_function;
@@ -68,6 +69,7 @@ impl FunctionDispatcher {
         functions.insert("createArray".to_string(), Box::new(create_array::CreateArray{}));
         functions.insert("div".to_string(), Box::new(div::Div{}));
         functions.insert("envvar".to_string(), Box::new(envvar::Envvar{}));
+        functions.insert("int".to_string(), Box::new(int::Int{}));
         functions.insert("max".to_string(), Box::new(max::Max{}));
         functions.insert("min".to_string(), Box::new(min::Min{}));
         functions.insert("mod".to_string(), Box::new(mod_function::Mod{}));