chore: import upstream snapshot with attribution

python/semantic_kernel/template_engine/blocks/val_block.py

@@ -0,0 +1,74 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+import logging
+from re import S, compile
+from typing import TYPE_CHECKING, Any, ClassVar
+
+from pydantic import model_validator
+
+from semantic_kernel.exceptions import ValBlockSyntaxError
+from semantic_kernel.template_engine.blocks.block import Block
+from semantic_kernel.template_engine.blocks.block_types import BlockTypes
+
+if TYPE_CHECKING:
+    from semantic_kernel.functions.kernel_arguments import KernelArguments
+    from semantic_kernel.kernel import Kernel
+
+logger: logging.Logger = logging.getLogger(__name__)
+
+VAL_BLOCK_REGEX = r"^(?P<quote>[\"'])(?P<value>.*)(?P=quote)$"
+
+VAL_BLOCK_MATCHER = compile(VAL_BLOCK_REGEX, flags=S)
+
+
+class ValBlock(Block):
+    """Create a value block.
+
+    A value block is used to represent a value in a template.
+    It can be used to represent any characters.
+    It needs to start and end with the same quote character,
+    can be both single or double quotes, as long as they are not mixed.
+
+    Examples:
+        'value'
+        "value"
+        'value with "quotes"'
+        "value with 'quotes'"
+
+    Args:
+        content - str : The content of the value block.
+        value - str: The value of the block.
+        quote - str: The quote used to wrap the value.
+
+    Raises:
+        ValBlockSyntaxError: If the content does not match the value block syntax.
+
+    """
+
+    type: ClassVar[BlockTypes] = BlockTypes.VALUE
+    value: str | None = ""
+    quote: str | None = "'"
+
+    @model_validator(mode="before")
+    @classmethod
+    def parse_content(cls, fields: Any) -> Any:
+        """Parse the content and extract the value and quote.
+
+        The parsing is based on a regex that returns the value and quote.
+        if the 'value' is already present then the parsing is skipped.
+        """
+        if isinstance(fields, Block) or "value" in fields:
+            return fields
+        content = fields.get("content", "").strip()
+        matches = VAL_BLOCK_MATCHER.match(content)
+        if not matches:
+            raise ValBlockSyntaxError(content=content)
+        if value := matches.groupdict().get("value"):
+            fields["value"] = value
+        if quote := matches.groupdict().get("quote"):
+            fields["quote"] = quote
+        return fields
+
+    def render(self, *_: "Kernel | KernelArguments | None") -> str:
+        """Render the value block."""
+        return self.value or ""