Support inline regex

schemars/tests/expected/validate.json

@@ -13,6 +13,7 @@
     "pair",
     "regex_str1",
     "regex_str2",
+    "regex_str3",
     "required_option",
     "tel",
     "x"
@@ -32,6 +33,10 @@
       "type": "string",
       "pattern": "^[Hh]ello\\b"
     },
+    "regex_str3": {
+      "type": "string",
+      "pattern": "^\\d+$"
+    },
     "contains_str1": {
       "type": "string",
       "pattern": "substring\\.\\.\\."

schemars/tests/validate.rs

@@ -14,6 +14,8 @@ pub struct Struct {
     regex_str1: String,
     #[validate(regex(path = "STARTS_WITH_HELLO", code = "foo"))]
     regex_str2: String,
+    #[validate(regex(pattern = r"^\d+$"))]
+    regex_str3: String,
     #[validate(contains = "substring...")]
     contains_str1: String,
     #[validate(contains(pattern = "substring...", message = "bar"))]

schemars_derive/src/attr/validation.rs

@@ -2,7 +2,7 @@ use super::parse_lit_str;
 use proc_macro2::TokenStream;
 use syn::ExprLit;
 use syn::NestedMeta;
-use syn::{Expr, Lit, Meta, MetaNameValue, Path};
+use syn::{Expr, Lit, Meta, MetaNameValue};
 
 #[derive(Debug, Default)]
 pub struct ValidationAttrs {
@@ -11,7 +11,7 @@ pub struct ValidationAttrs {
     pub length_equal: Option<Expr>,
     pub range_min: Option<Expr>,
     pub range_max: Option<Expr>,
-    pub regex: Option<Path>,
+    pub regex: Option<Expr>,
     pub contains: Option<String>,
     pub required: bool,
     pub format: Option<&'static str>,
@@ -84,7 +84,9 @@ impl ValidationAttrs {
                     path,
                     lit: Lit::Str(regex),
                     ..
-                })) if path.is_ident("regex") => self.regex = parse_lit_str(regex).ok(),
+                })) if path.is_ident("regex") => {
+                    self.regex = parse_lit_str::<syn::ExprPath>(regex).ok().map(Expr::Path)
+                }
 
                 NestedMeta::Meta(Meta::List(meta_list)) if meta_list.path.is_ident("regex") => {
                     self.regex = meta_list.nested.iter().find_map(|x| match x {
@@ -92,7 +94,17 @@ impl ValidationAttrs {
                             path,
                             lit: Lit::Str(regex),
                             ..
-                        })) if path.is_ident("path") => parse_lit_str(regex).ok(),
+                        })) if path.is_ident("path") => {
+                            parse_lit_str::<syn::ExprPath>(regex).ok().map(Expr::Path)
+                        }
+                        NestedMeta::Meta(Meta::NameValue(MetaNameValue {
+                            path,
+                            lit: Lit::Str(regex),
+                            ..
+                        })) if path.is_ident("pattern") => Some(Expr::Lit(syn::ExprLit {
+                            attrs: Vec::new(),
+                            lit: Lit::Str(regex.clone()),
+                        })),
                         _ => None,
                     });
                 }