Normalize first
Store the original string, then compute comparison keys such as NFC or NFKC where appropriate.
Public boundary
Unicode governance for semantic glyph systems
The public interchange layer and the internal semantic-stability layer should stay deliberately separate.
Characters are not glyphs.
Unicode and ISO/IEC 10646 provide the public character repertoire and encoding layer. They do not make font-specific glyph images into independent public meanings.
A semantic glyph interpreter must distinguish code points, grapheme clusters, rendered glyphs, SVG forms, and inferred concepts before it claims any interpretation.
Design rule
The internal semantic layer may reason over visual structure, embeddings, ontology tags, and validation traces. Visible public output should remain assigned Unicode characters or valid public sequences.
Compatibility checklist.
Segment correctly
Use grapheme-cluster boundaries for user-perceived characters rather than single-code-point assumptions.
Resolve script context
Use script properties and script extensions; do not treat Unicode blocks as script identity.
Respect variation rules
Treat variation selectors and emoji-style sequences as meaningful only when they are valid public sequences.
Reject private authority
Private-use characters may exist by private agreement, but the converter should not promote them to public semantics.
Expose provenance
Every output should show public symbol status, retrieval lanes, ontology checks, and confidence.
What not to do.
No hidden codebook
Do not map arbitrary private glyphs to secret public meanings without inspection.
No font-specific semantics
Do not treat a style variation as a new character unless public standards encode that distinction.
No visual collapse
Do not equate visual similarity with semantic identity; homoglyphs and spoofing matter.
No single-layer lookup
Do not collapse Unicode, glyph image, ontology, and canonical meaning into one registry row.
The layered compromise.
The safest design is neither a pure text lookup nor an unconstrained glyph-invention system. It is layered: public Unicode for interchange, visual decomposition for evidence, ontology for validity, and stability scoring over time.
Public layerAssigned Unicode and valid sequences
Conformance layerNormalization, graphemes, scripts, variation
Semantic layerEmbeddings, ontology, evidence traces
Stability layerPhase-lock, drift, human review