(* LAKA SEO Grammar — EBNF v1.0 *)

seo_program          = program_header,
                       business_clause,
                       audience_clause,
                       demand_clause,
                       asset_clause,
                       graph_clause,
                       outcome_clause,
                       constraint_clause,
                       change_clause,
                       decision_clause ;

program_header       = "SEO", identifier, version ;

business_clause      = "GOAL", goal,
                       "FOR", business,
                       [ "OFFER", offer ],
                       "VALUED_BY", value_event ;

audience_clause      = "AUDIENCE", audience,
                       "UNDER", condition_list,
                       "IN_STATE", journey_state ;

demand_clause        = "SEEKING", task,
                       "WITH_INTENT", intent,
                       "ABOUT", semantic_subject,
                       "USING", query_cluster,
                       [ "EXCLUDING", exclusion_list ] ;

asset_clause         = "SERVED_BY", canonical_asset,
                       "AS", page_type,
                       "IN_FORMAT", format_choice,
                       "SUPPORTED_BY", evidence_choice,
                       "LEADING_TO", next_action ;

graph_clause         = "CONNECTED_BY", graph_spec ;

outcome_clause       = "MEASURED_BY", primary_metric,
                       [ "SECONDARY", metric_list ],
                       [ "GUARDED_BY", guardrail_list ] ;

constraint_clause    = "CONSTRAINED_BY", constraint_list ;

change_clause        = "LAKA", laka_level,
                       "CHANGE", change_spec,
                       "DESCRIBED_BY", change_signature ;

decision_clause      = if_expression,
                       "UNTIL", stop_condition ;

if_expression        = "IF", boolean_expression,
                       "THEN", action,
                       [ "ELSE", alternative_action ] ;

boolean_expression   = boolean_term,
                       { boolean_operator, boolean_term } ;

boolean_term         = predicate
                     | "NOT", predicate
                     | "(", boolean_expression, ")" ;

boolean_operator     = "AND" | "OR" | "XOR" ;

predicate            = identifier, comparison_operator, value
                     | function_call ;

comparison_operator  = "=" | "!=" | ">" | ">=" | "<" | "<="
                     | "IN" | "MATCHES" | "EXISTS" ;

function_call        = identifier, "(", [ argument_list ], ")" ;
argument_list        = value, { ",", value } ;

change_spec          = "OBJECT", object,
                       "CONDITIONS", condition_list,
                       "ACTIONS", action_list,
                       "TOOLS", tool_list,
                       "RESOURCES", resource_list,
                       "OUTCOMES", outcome_list,
                       "FEEDBACK", feedback_list,
                       "CONSTRAINTS", constraint_list,
                       "VALUE", value_statement,
                       "FAILURE_MODE", failure_mode_list ;

change_signature     = "MAGNITUDE", magnitude,
                       "RATE", rate,
                       "DIRECTION", direction,
                       "SCOPE", scope,
                       "DEPTH", depth,
                       "DURATION", duration,
                       "FREQUENCY", frequency,
                       "ACCELERATION", acceleration,
                       "VARIABILITY", variability,
                       "DETECTABILITY", detectability,
                       "REVERSIBILITY", reversibility,
                       "PROPAGATION", propagation,
                       "AMPLIFICATION", amplification,
                       "ACCUMULATION", accumulation ;

semantic_subject     = concept | entity | relation_expression ;
relation_expression  = semantic_node, relation, semantic_node ;
semantic_node        = concept | entity | attribute | attribute_value ;

query_cluster        = "CLUSTER", identifier,
                       "{", representative_query,
                       { ",", query_variant },
                       "}" ;

canonical_asset      = "CANONICAL", url,
                       [ "SUPPORT", "{", url, { ",", url }, "}" ] ;

format_choice        = format, { "OR", format } ;
evidence_choice      = evidence, { "OR", evidence } ;

graph_spec           = "{", graph_edge, { ",", graph_edge }, "}" ;
graph_edge           = url, edge_type, anchor_text, url ;

condition_list       = condition, { "AND", condition } ;
exclusion_list       = exclusion, { "AND", exclusion } ;
metric_list          = metric, { ",", metric } ;
guardrail_list       = guardrail, { ",", guardrail } ;
constraint_list      = constraint, { ",", constraint } ;
action_list          = action, { ",", action } ;
tool_list            = tool, { ",", tool } ;
resource_list        = resource, { ",", resource } ;
outcome_list         = outcome, { ",", outcome } ;
feedback_list        = feedback, { ",", feedback } ;
failure_mode_list    = failure_mode, { ",", failure_mode } ;

goal                  = string ;
business              = string ;
offer                 = string ;
value_event           = string ;
audience              = string ;
condition             = string ;
task                  = task_verb, task_object ;
task_verb             = "DEFINE" | "LEARN" | "DISCOVER" | "DIAGNOSE"
                      | "COMPARE" | "CALCULATE" | "LOCATE" | "VERIFY"
                      | "PLAN" | "IMPLEMENT" | "TROUBLESHOOT" | "BUY"
                      | "USE" | "MAINTAIN" | "RENEW" | "REFER" ;
task_object           = string ;

intent                = "INFORMATIONAL" | "COMPARATIVE"
                      | "COMMERCIAL_INVESTIGATION" | "TRANSACTIONAL"
                      | "NAVIGATIONAL" | "LOCAL" | "SUPPORT"
                      | "RETENTION" | "REPUTATION" ;

journey_state         = "UNAWARE" | "PROBLEM_AWARE" | "SOLUTION_AWARE"
                      | "OPTION_EVALUATION" | "DECISION"
                      | "IMPLEMENTATION" | "USE" | "RETENTION"
                      | "ADVOCACY" ;

page_type             = "SERVICE_PAGE" | "PRODUCT_PAGE" | "CATEGORY"
                      | "GUIDE" | "COMPARISON" | "CALCULATOR"
                      | "DIAGNOSTIC" | "TEMPLATE" | "CHECKLIST"
                      | "DIRECTORY" | "LOCATION_PAGE" | "CASE_STUDY"
                      | "DATASET" | "BENCHMARK" | "GLOSSARY" | "FAQ"
                      | "VIDEO" | "INTERACTIVE" | "API" ;

format                = "TEXT" | "TABLE" | "IMAGE" | "VIDEO" | "AUDIO"
                      | "MAP" | "FORM" | "CALCULATOR" | "DECISION_TREE"
                      | "DATASET" | "DOWNLOAD" | "INTERACTIVE" ;

evidence              = "FIRSTHAND_EXPERIENCE" | "ORIGINAL_DATA"
                      | "REPRODUCIBLE_TEST" | "PRIMARY_SOURCE"
                      | "EXPERT_REVIEW" | "CASE_STUDY"
                      | "DEMONSTRATION" | "METHODOLOGY"
                      | "LIMITATIONS" ;

edge_type             = "DEFINITION_OF" | "PREREQUISITE_OF"
                      | "EXAMPLE_OF" | "EVIDENCE_FOR" | "COMPARISON_TO"
                      | "ALTERNATIVE_TO" | "STEP_BEFORE" | "STEP_AFTER"
                      | "SUPPORTS" | "CONVERTS_TO"
                      | "LOCATION_VARIANT_OF" | "SERVICE_VARIANT_OF" ;

laka_level            = "BASELINE" | "MINOR" | "MAJOR"
                      | "STRUCTURAL" | "PARADIGM" ;

magnitude             = "NEGLIGIBLE" | "SMALL" | "MEDIUM"
                      | "LARGE" | "TRANSFORMATIONAL" ;
rate                  = "IMMEDIATE" | "FAST" | "GRADUAL" | "SLOW" | "UNKNOWN" ;
direction             = "POSITIVE" | "NEGATIVE" | "MIXED" | "NEUTRAL" ;
scope                 = "ELEMENT" | "PAGE" | "CLUSTER" | "TEMPLATE"
                      | "SITE" | "MARKET" ;
depth                 = "COPY" | "BEHAVIOR" | "DOCUMENT"
                      | "ARCHITECTURE" | "BUSINESS_MODEL" ;
duration              = "TRANSIENT" | "CAMPAIGN" | "PERSISTENT" | "PERMANENT" ;
frequency             = "ONCE" | "PERIODIC" | "EVENT_DRIVEN" | "CONTINUOUS" ;
acceleration          = "DECAYING" | "LINEAR" | "COMPOUNDING" | "VOLATILE" ;
variability           = "LOW" | "MODERATE" | "HIGH" | "UNKNOWN" ;
detectability         = "DIRECT" | "PROXY" | "MODELED" | "LATENT" ;
reversibility         = "EASY" | "MODERATE" | "DIFFICULT" | "IRREVERSIBLE" ;
propagation           = "ISOLATED" | "LINKED" | "TEMPLATE_WIDE"
                      | "SITE_WIDE" | "ECOSYSTEM" ;
amplification         = "NONE" | "INTERNAL_GRAPH" | "EXTERNAL_CITATIONS"
                      | "BRAND" | "NETWORK" ;
accumulation          = "NONE" | "EPISODIC" | "STOCK_BUILDING" | "COMPOUNDING" ;

object                = string ;
action                = string ;
alternative_action    = string ;
tool                  = string ;
resource              = string ;
outcome               = string ;
feedback              = string ;
constraint            = string ;
value_statement       = string ;
failure_mode          = string ;
stop_condition        = string ;
primary_metric        = metric ;
metric                = string ;
guardrail             = string ;
next_action           = string ;
exclusion             = string ;
concept               = string ;
entity                = string ;
attribute             = string ;
attribute_value       = string ;
relation              = string ;
representative_query  = string ;
query_variant         = string ;
anchor_text           = string ;
url                   = string ;
identifier            = letter, { letter | digit | "_" | "-" } ;
version               = digit, ".", digit ;
value                 = string | number | boolean ;
boolean               = "true" | "false" ;
number                = digit, { digit }, [ ".", digit, { digit } ] ;
string                = '"', { character - '"' }, '"' ;
letter                = "A"…"Z" | "a"…"z" ;
digit                 = "0"…"9" ;
character             = ? any Unicode character ? ;