Tools for CQP queries.

Source: R/utils.R

Test whether a character string is a CQP query, or turn a character vector into CQP queries.

is.cqp(query)

check_cqp_query(query, warn = TRUE)

as.cqp(query, normalise.case = FALSE, collapse = FALSE)

Arguments

query

A character vector with at least one CQP query.
warn

A (length-one) logical value, whether to issue a warning if a query may be buggy.
normalise.case

A logical value, if TRUE, a flag will be added to the query/queries to omit matching case.
collapse

A logical value, whether to collapse the queries into one.

Value

is.cqp returns a logical value, as.cqp a character vector, check_cqp_query a logical value that is TRUE if all queries are valid, or FALSE if not.

Details

The is.cqp function guesses whether query is a CQP query and returns the respective logical value (TRUE/FALSE).

The as.cqp function takes a character vector as input and converts it to a CQP query by putting the individual strings in quotation marks.

The check_cqp_query-function will check that opening quotation marks are matched by closing quotation marks, to prevent crashes of CQP and the R session.

References

CQP Query Language Tutorial (http://cwb.sourceforge.net/files/CQP_Tutorial.pdf)

Examples

is.cqp("migration") # will return FALSE

#> [1] FALSE
is.cqp('"migration"') # will return TRUE

#> [1] TRUE
is.cqp('[pos = "ADJA"] "migration"') # will return TRUE

#> [1] TRUE

as.cqp("migration")

#>       migration 
#> "\"migration\"" 
as.cqp(c("migration", "diversity"))

#>       migration       diversity 
#> "\"migration\"" "\"diversity\"" 
as.cqp(c("migration", "diversity"), collapse = TRUE)

#> [1] "(\"migration\"|\"diversity\")"
as.cqp("migration", normalise.case = TRUE)

#>          migration 
#> "\"migration\" %c" 

check_cqp_query('"Integration.*"') # TRUE, the query is ok

#> "Integration.*" 
#>            TRUE 
check_cqp_query('"Integration.*') # FALSE, closing quotation mark is missing

#> Warning: An issue occurred when checking query: "Integration.*
#> Number of quotation marks is not divisable by 2: Opening quotation marks are not matched by closing quotation marks, or vice versa. Aborting to avoid a potential crash of CQP and the entire R session. Please check query.
#> "Integration.* 
#>          FALSE 
check_cqp_query("'Integration.*") # FALSE, closing quotation mark is missing

#> Warning: An issue occurred when checking query: 'Integration.*
#> Number of quotation marks is not divisable by 2: Opening quotation marks are not matched by closing quotation marks, or vice versa. Aborting to avoid a potential crash of CQP and the entire R session. Please check query.
#> 'Integration.* 
#>          FALSE 
check_cqp_query(c("'Integration.*", '"Integration.*')) # FALSE too

#> Warning: An issue occurred when checking query: 'Integration.*
#> Number of quotation marks is not divisable by 2: Opening quotation marks are not matched by closing quotation marks, or vice versa. Aborting to avoid a potential crash of CQP and the entire R session. Please check query.
#> Warning: An issue occurred when checking query: "Integration.*
#> Number of quotation marks is not divisable by 2: Opening quotation marks are not matched by closing quotation marks, or vice versa. Aborting to avoid a potential crash of CQP and the entire R session. Please check query.
#> 'Integration.* "Integration.* 
#>          FALSE          FALSE