1 files changed, 87 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/development/tools/poetry2nix/poetry2nix/semver.nix b/nixpkgs/pkgs/development/tools/poetry2nix/poetry2nix/semver.nix
new file mode 100644
index 000000000000..0ef1d4c316ac
--- /dev/null
+++ b/nixpkgs/pkgs/development/tools/poetry2nix/poetry2nix/semver.nix
@@ -0,0 +1,87 @@
+{ lib, ireplace }:
+let
+  inherit (builtins) elemAt match;
+  operators =
+    let
+      matchWildCard = s: match "([^*])(\\.[*])" s;
+      mkComparison = ret: version: v: builtins.compareVersions version v == ret;
+      mkIdxComparison = idx: version: v:
+        let
+          ver = builtins.splitVersion v;
+          minor = builtins.toString (lib.toInt (elemAt ver idx) + 1);
+          upper = builtins.concatStringsSep "." (ireplace idx minor ver);
+        in
+        operators.">=" version v && operators."<" version upper;
+      dropWildcardPrecision = f: version: constraint:
+        let
+          m = matchWildCard constraint;
+          hasWildcard = m != null;
+          c = if hasWildcard then (elemAt m 0) else constraint;
+          v =
+            if hasWildcard then (builtins.substring 0 (builtins.stringLength c) version)
+            else version;
+        in
+        f v c;
+    in
+    {
+      # Prefix operators
+      "==" = dropWildcardPrecision (mkComparison 0);
+      ">" = dropWildcardPrecision (mkComparison 1);
+      "<" = dropWildcardPrecision (mkComparison (-1));
+      "!=" = v: c: ! operators."==" v c;
+      ">=" = v: c: operators."==" v c || operators.">" v c;
+      "<=" = v: c: operators."==" v c || operators."<" v c;
+      # Semver specific operators
+      "~" = mkIdxComparison 1;
+      "^" = mkIdxComparison 0;
+      "~=" = v: c:
+        let
+          # Prune constraint
+          parts = builtins.splitVersion c;
+          pruned = lib.take ((builtins.length parts) - 1) parts;
+          upper = builtins.toString (
+            (lib.toInt (builtins.elemAt pruned (builtins.length pruned - 1))) + 1
+          );
+          upperConstraint = builtins.concatStringsSep "." (ireplace (builtins.length pruned - 1) upper pruned);
+        in
+        operators.">=" v c && operators."<" v upperConstraint;
+      # Infix operators
+      "-" = version: v: operators.">=" version v.vl && operators."<=" version v.vu;
+      # Arbitrary equality clause, just run simple comparison
+      "===" = v: c: v == c;
+      #
+    };
+  re = {
+    operators = "([=><!~^]+)";
+    version = "([0-9.*x]+)";
+  };
+  parseConstraint = constraint:
+    let
+      constraintStr = builtins.replaceStrings [ " " ] [ "" ] constraint;
+      # The common prefix operators
+      mPre = match "${re.operators} *${re.version}" constraintStr;
+      # There is also an infix operator to match ranges
+      mIn = match "${re.version} *(-) *${re.version}" constraintStr;
+    in
+    (
+      if mPre != null then {
+        op = elemAt mPre 0;
+        v = elemAt mPre 1;
+      }
+      # Infix operators are range matches
+      else if mIn != null then {
+        op = elemAt mIn 1;
+        v = {
+          vl = (elemAt mIn 0);
+          vu = (elemAt mIn 2);
+        };
+      }
+      else throw "Constraint \"${constraintStr}\" could not be parsed"
+    );
+  satisfiesSemver = version: constraint:
+    let
+      inherit (parseConstraint constraint) op v;
+    in
+    if constraint == "*" then true else operators."${op}" version v;
+in
+{ inherit satisfiesSemver; }