STL Syntax Quick Reference

One-page reference card for STL (Semantic Tension Language) syntax.

Statement Structure

[Source] -> [Target] ::mod(key=value, key=value, ...)

Component	Syntax	Required
Source anchor	`[Name]` or `[Namespace:Name]`	Yes
Arrow	`->` or `→`	Yes
Target anchor	`[Name]` or `[Namespace:Name]`	Yes
Modifier block	`::mod(key=value, ...)`	No

Anchors

[Simple_Name]                    # Basic anchor
[Physics:Energy]                 # Namespaced anchor
[Physics.Quantum:Quark]          # Hierarchical namespace
[黄帝内经]                        # Unicode anchor

Valid characters: Letters (any script), digits, underscores. Max 64 characters.

Invalid:

[]                   # Empty
[ Spaced ]           # Whitespace
[Not Valid!]         # Special characters
[Nested [Anchor]]    # Nesting

Reserved names: NULL, UNDEFINED, ANY, NONE, TRUE, FALSE, SYSTEM, GLOBAL, LOCAL

Arrows

[A] -> [B]           # ASCII arrow
[A] → [B]            # Unicode arrow (U+2192)

Both forms are identical. Direction matters: [A] -> [B] is not the same as [B] -> [A].

Modifiers

[A] -> [B] ::mod(confidence=0.85, rule="causal")

Value Types

Type	Syntax	Examples
String	`"quoted"`	`rule="causal"`, `source="doi:10.1234"`
Float	bare number	`confidence=0.85`, `strength=0.9`
Integer	bare number	`priority=5`
Boolean	`true` / `false`	`verified=true`
DateTime	ISO 8601 string	`timestamp="2025-01-15T10:00:00Z"`

Standard Modifier Fields

Temporal: time, duration, frequency, tense

Spatial: location, domain, scope

Logical: confidence (0.0-1.0), certainty (0.0-1.0), necessity, rule

Provenance: source, author, timestamp, version

Affective: emotion, intensity (0.0-1.0), valence

Value: value, alignment, priority

Causal: strength (0.0-1.0), cause, effect, conditionality

Cognitive: intent, focus, perspective

Mood: mood, modality

Any key not listed above is treated as a custom modifier and preserved by the parser.

Chained Paths

[A] -> [B] -> [C] ::mod(confidence=0.85)

Equivalent to two statements. The modifier applies to the last edge ([B] -> [C]).

Keep chains to 3-5 nodes maximum. Break longer chains into separate statements.

Multi-line Modifiers

[Rain] -> [Flooding] ::mod(
  rule="causal",
  confidence=0.85,
  strength=0.80,
  location="Urban_Area"
)

Whitespace and newlines inside ::mod(...) are ignored.

Multiple Modifier Blocks

[Action] -> [Result]
  ::mod(time="Present")
  ::mod(confidence=0.85)
  ::mod(source="doc://report.pdf")

Multiple ::mod() blocks on the same statement are merged. Limit to 5-7 modifier fields per statement total.

Comments

# This is a comment
[A] -> [B] ::mod(confidence=0.9)  # Inline comment

Comments begin with # and extend to end of line.

Rule Types

Value	Meaning	Example
`"causal"`	Cause-effect relationship	Rain causes flooding
`"logical"`	Logical implication or deduction	Premises imply conclusion
`"empirical"`	Evidence-based observation	Experiment confirms theory
`"definitional"`	Definition or categorization	Water is H2O
`"correlative"`	Statistical correlation	Exercise correlates with health

Confidence Calibration

Range	Usage
0.95 - 1.0	Definitional truths, mathematical facts
0.85 - 0.94	Well-established facts, strong evidence
0.70 - 0.84	Generally accepted, moderate evidence
0.50 - 0.69	Probable but uncertain, limited evidence
0.30 - 0.49	Speculative, weak evidence
0.00 - 0.29	Highly uncertain, hypothetical

9 Anchor Types

Type	Layer	Purpose
Concept	Semantic	Abstract ideas, theories, categories
Relational	Semantic	Logical or semantic relations
Event	Entity	Actions, processes, temporal events
Entity	Entity	Physical or perceivable objects
Name	Entity	Proper nouns (people, places, orgs)
Agent	Structural	Active subjects with agency
Question	Structural	Open inquiries, hypotheses
Verifier	Structural	Evaluation and testing mechanisms
PathSegment	Structural	Intermediate states, transitions

6 Path Types

Type	Semantic Function
Semantic	Definitional, categorical
Action	Agency and intentionality
Cognitive	Epistemic relations
Causal	Cause-effect mechanisms
Inferential	Logical reasoning
Reflexive	Self-reference

Complete Example

# Scientific knowledge representation
[Theory_Relativity] -> [Prediction_TimeDilation] ::mod(
  rule="logical",
  confidence=0.99,
  author="Einstein",
  source="doi:10.1002/andp.19053221004",
  domain="physics"
)

[Prediction_TimeDilation] -> [Experiment_GPS] ::mod(
  rule="empirical",
  confidence=0.97,
  strength=0.95
)

# Causal chain
[Heavy_Rain] -> [Flooding] ::mod(
  rule="causal",
  confidence=0.85,
  strength=0.80,
  conditionality="Sufficient"
)

File Extensions

Extension	Purpose
`.stl`	STL document
`.stl.schema`	STL domain schema