JACU

JACU is an abbreviated way to refer to a proposal to use simplified connectives as initially proposed by la selpa'i in a March 2014 blog post and expanded in a September 2016 blog post . It takes its name from the collocation of connective cmavo of selma'o JA with cu, enabling those particles to join bridi tails in contexts where they would otherwise join selbri within a tanru.

Details

JA* (logical afterthought connectives)

The following cmavo of selma'o JA are recommended as general purpose logical "afterthought" connectives:

• ja
• je
• jo
• ju

For purposes of disambiguating the new syntax of the proposed usage, these cmavo will be described as belonging to selma'o JA*.

Uses of JA* per "JACU"

connective type	example w/o "JACU"	"JACU" example	selma'o
logical sumti connective	ko'a .a ko'e	ko'a ja ko'e	A -> JA*
logical bridi tail connective	broda gi'a brode	broda ja cu brode	GIhA -> JA* + CU
logical tanru connective	broda ja brode	broda ja brode	JA -> JA*
logical(*) relative clause connective	undefined	poi broda je poi brode	undefined -> JA*

ji (logical afterthought connective questions)

ji, which is described in CLL (14.13) as a dedicated sumti connective belonging to selma'o A. Under "JACU", it is proposed to be treated with the same expanded range as a member of selma'o JA*.

Uses of ji per "JACU"

logical connective question type	example w/o "JACU"	"JACU" example	selma'o
logical sumti connective	ko'a ji ko'e	ko'a ji ko'e	A -> JA*
logical bridi tail connective	broda gi'i brode	broda ji cu brode	GIhA -> JA* + CU
logical tanru connective	broda je'i brode	broda ji brode	JA -> JA*
logical relative clause connective	undefined	poi broda ji poi brode	undefined -> JA*

GA* / GUhA* (forethought connectives)

Analogous to the use of JA* cmavo as universal logical afterthought connectives, "JACU" proposes a unified pattern for forethought connectives: ga or gu + JA*, retaining gi as a delimiter.

For purposes of disambiguating the new syntax of the proposed usage, ga will be described as belonging to selma'o GA* and gu will be described as a member of selma'o GUhA*.

Uses of GA* AND GUhA per "JACU"

connective type	example w/o "JACU"	"JACU" example	selma'o
sumti connective	ga ko'a gi ko'e	ga ja ko'a gi ko'e	GA -> GA* + JA*
bridi tail connective	ga broda gi brode	ga ja broda gi brode	GA -> GA* + JA*
tanru connective	gu'a broda gi brode	gu ja broda gi brode	GUhA -> GUhA* + JA*
relative clause connective	undefined	ga ja poi broda gi poi brode	undefined -> GA* + JA*

Forethought connective questions are possible in each case by using ji, e.g. ga ji ko'a gi ko'e.

GI and GIhI*(chainable forethought connectives)

Per CLL, forethought connectives can only join two terms. Per "JACU", a forethought connective may have any number of terms.

Uses of chainable GI per "JACU"

connective type	"JACU" example
sumti connective	ga ja ko'a gi ko'e gi ko'i
bridi tail connective	ga ja broda gi brode gi brodi
tanru connective	gu ja broda gi brode gi brodi
relative clause connective	ga ja poi broda gi poi brode gi poi brodi

Following the example of zantufa, gi'i is borrowed from selma'o GIhA to act as a terminator for forethought connectives. In this document, gi'i will be described as belonging to selma'o GIhI*.

JOI (non-logical connectives)

"JACU" proposes that wherever JA* may be used, non-logical connectives from JOI could also be applied, especially joi and jo'u.

Uses of JOI per "JACU"

connective type	afterthought example	forethought example
non-logical sumti connective	ko'a joi ko'e	ga joi ko'a gi ko'e
bridi tail connective	broda joi cu brode	ga joi broda gi brode
tanru connective	broda joi brode	gu joi broda gi brode
relative clause connective	poi broda joi poi brode	ga joi poi broda gi poi brode

"JACU" proposes similar treatment for the mathematical operators of VUhU.

Rationale

Simplicity

Instead of different forms for sumti, bridi tails, tanru and relative clauses, "JACU" limits the different forms to what is strictly necessary to avoid ambiguity, e.g. ga je broda gi brode (bridi tails) vs gu je broda gi brode (tanru).

The resulting system is much smaller, which is a boon to those learning the language as well as those writing software to process it.

Complexity

connective system	logical connective cmavo	count
CLL	.a, .e, .o, .u, gi'a, gi'e, gi'o, gi'u, ja, je, jo, ju, zi'e, ji, gi'i, je'i, ga, ge, go, gu, gi, gu'a, gu'e, gu'o, gu'u, ge'i, gu'i	27
"JACU"	ja, je, jo, ju, ji, ga, gu, gi, gi'i	9

Consistency and completeness

"JACU" connectives handle every type of argument. CLL (14.20) connectives do not.

Afterthought connectives

argument type	logical		non-logical
	CLL	"JACU"	CLL	"JACU"
sumti	ko'a .a ko'e	ko'a ja ko'e	ko'a joi ko'e	ko'a joi ko'e
bridi tail	broda gi'a brode	broda ja cu brode	undefined	broda joi cu brode
tanru	broda ja brode	broda ja brode	broda joi brode	broda joi brode
relative clause	undefined	poi broda ja poi brode	poi broda zi'e poi brode	poi broda joi poi brode

Forethought connectives

argument type	logical		non-logical
	CLL	"JACU"	CLL	"JACU"
sumti	ga ko'a gi ko'e	ga ja ko'a gi ko'e	joi gi ko'a gi ko'e	ga joi ko'a gi ko'e
bridi tail	ga broda gi brode	ga ja broda gi brode	joi gi broda gi brode	ga joi broda gi brode
tanru	gu'a broda gi brode	gu ja broda gi brode	undefined	gu joi broda gi brode
relative clause	undefined	ga ja poi broda gi poi brode	undefined	ga joi poi broda gi poi brode

Freedom from obsolete technical constraints

At the time that lojban and its predecessor loglan were designed, tools for parsing text were constrained in ways that influenced the design of the language. Limitations in the number of tokens that a parser could simultaneously consider ("lookahead") made it expedient to assign different connectives for different kinds of arguments, e.g. .a for sumti, ja for tanru, gi'a for bridi tails, etc.

Since 2003, the camxes lineage of parsers has been adopted by the lojban community as the de facto standard. These parsers are based on a newer parsing technology ("Parsing Expression Grammars") which are comparatively unconstrained in terms of lookahead.