Error Messages

a_/1 atom declared subsumed by type $T$

Subsumption over a_/1 atoms has a fixed definition. Subtyping specifications with a_/1 atoms are not allowed.

add_to could not unify $FS_{1}$ and $FS_{2}$

The unification between feature structures $FS_{1}$ and $FS_{2}$ failed.

add_to could not unify paths $\pi$ and $\phi$ in $FS$

The unification between paths $\pi$ and $\phi$ failed in feature structure $FS$ failed.

add_to could not inequate $FS_{1}$ and $FS_{2}$

The inequation between features structures $FS_{1}$ and $FS_{2}$ could not been satisfied.

add_to could not add feature $F$ to $FS$

The value of feature $F$ is not unifiable with the similar value in feature structure $FS$.

add_to could not add undefined macro $M$ to $FS$

Macro $M$ used in feature structure $FS$ is undefined.

add_to could not add incompatible type $T$ to $FS$

Type $T$ is not compatible with the type of feature structure $FS$.

add_to could not add undefined type $T$ to $FS$

Type $T$ in feature structure $FS$ is undefined.

add_to could not add ill formed complex description $D$ to $FS$

Description $D$ is ill formed and could not be unified with feature structure $FS$

appropriateness cycle following path $\pi$ from type $T$

There is a sequence of features $\pi$ which must be defined for objects of type $T$ where the value must be of type $T$.

bot has appropriate features

The most general type, $\bot$, cannot have any appropriate features.

bot has constraints

The most general type, $\bot$, must not have cons constraints.

cats> value with sort $S$ is not a valid list argument

An argument of cats> was detected at run-time, which is not of a type subsumed by list.

consistent $T_{1}$ and $T_{2}$ have multiple mgus $Ts$

Types $T_{1}$ and $T_{2}$ have the non singleton set $Ts$ as their set of most general unifiers.

constraint declaration given for atom

a_/1 atoms must not have cons constraints.

description uses unintroduced feature $F$

A description uses the feature $F$ which has not been defined as appropriate for any types.

edge/2: arguments must be non-negative

The arguments to edge/2 represent nodes in a parsing chart, and thus must be non-negative integers.

edge/2: first argument must be < second argument

The arguments to edge/2 represent nodes in a parsing chart. Edges only span from one node to an equal or greater valued node. edge/2 shows edges where the other node has a greater value. empty/0 shows edges where the node has an equal value.

extensional type $E$ is not maximal

Type $E$ is declared extensional but does not observe the maximality restriction.

feature $F$ multiply introduced at $Ts$

The feature $F$ is introduced at the types in $Ts$, which are not comparable with one another.

illegal variable occurence in $T$ sub $Ss$ (intro $FRs$)

In subtype/feature specifications, neither $T$ or any of the types in $Ss$ or $FRs$, or any of the features in $FRs$ can be unbound variables. If a value restriction is an a_/1 atom, that atom can be unbound, or contain unbound variables, but the a_/1 operator must still appear.

incompatible restrictions on feature $F$ at type $T$ are $Ts$

The inherited restrictions, consisting of types $Ts$, on the value of $F$ at type $T$ are not consistent.

invalid line $\phi$ in rule

A line of a grammar rule is neither a goal nor a category description.

lexical rule $LR$ lacks morphs specification

The obligatory morphs part of lexical rule $LR$ is missing.

multiple constraint declaration error for $T$

More than one cons declaration exists for type $T$.

multiple feature specifications for type $T$

The appropriate features of $T$ can be introduced along with subtyping or by themselves, but there can only be one declaration of appropriate features.

multiple specification for $F$ in declaration of $T$

More than one restriction on the value of feature $F$ is given in the definition of type $T$.

no lexical entry for $W$

Expression $W$ is used, but has no lexical entry.

pathval: illegal path specified - $\pi$

Path $\pi$ is not a valid path specification for the given feature structure.

rule $R$ has multiple sem_head> specifications

More than one semantic head declaration was found in grammar rule $R$.

rule $R$ has no cat> cats> or sem_head> specification

The grammar rule named $R$ is empty in that it does not have any daughter specification.

rule $R$ has wrongly placed sem_goal> specifications

A sem_goal> specification occurs somewhere other than immediately before or immediately after a sem_head> specification in rule $R$.

subtype/feature specification given for a_/1 atom

Subsumption over a_/1 atoms has a fixed definition, and they can have no features. Subtype or feature specifications for them are not allowed.

subtyping cycle at $T$

The subsumption relation specified is not anti-symmetric. It can be inferred that the type $T$ is a proper subtype of itself.

subtype $T_{1}$ used in $T_{2}$ undeclared

Undefined type $T_{1}$ declared as subtype in definition of $T_{2}$.

$T$ multiply defined

There is more than one definition of type $T$.

$T$ subsumes bot

$T$ is declared as subsuming the most general type, $\bot$.

$T_{1}$ used in appropriateness definition of $T_{2}$ undeclared

Undefined type $T_{1}$ used as value restriction in definition of $T_{2}$.

undefined macro $M$ used in description

A description uses a macro which is not defined.

undefined type $T$ used in description

A description uses a type $T$ which is not defined.

undefined feature $F$ used in path $\pi$

A path $\pi$ of features uses undefined feature $F$ in a description.

unsatisfiable lexical entry for $W$

Word $W$ has a lexical entry which has no satisfying feature structure.

upward closure fails for $F$ in $S1$ and $S2$

$S1$ subsumes $S2$, but the value restriction for $F$ at $S1$ does not subsume the value restriction for $F$ at $S2$.